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Sample records for argon radio-frequency glow

  1. Characteristics of atmospheric-pressure, radio-frequency glow discharges operated with argon added ethanol

    International Nuclear Information System (INIS)

    Rf, atmospheric-pressure glow discharge (APGD) plasmas with bare metal electrodes have promising prospects in the fields of plasma-aided etching, thin film deposition, disinfection and sterilization, etc. In this paper, the discharge characteristics are presented for the rf APGD plasmas generated with pure argon or argon-ethanol mixture as the plasma-forming gas and using water-cooled, bare copper electrodes. The experimental results show that the breakdown voltage can be reduced significantly when a small amount of ethanol is added into argon, probably due to the fact that the Penning ionization process is involved, and a pure α-mode discharge can be produced more easily with the help of ethanol. The uniformity of the rf APGDs of pure argon or argon-ethanol mixtures using bare metallic electrodes is identified with the aid of the intensified charge coupled device images

  2. Characteristics of atmospheric-pressure, radio-frequency glow discharges operated with argon added ethanol

    Science.gov (United States)

    Sun, Wen-Ting; Li, Guo; Li, He-Ping; Bao, Cheng-Yu; Wang, Hua-Bo; Zeng, Shi; Gao, Xing; Luo, Hui-Ying

    2007-06-01

    Rf, atmospheric-pressure glow discharge (APGD) plasmas with bare metal electrodes have promising prospects in the fields of plasma-aided etching, thin film deposition, disinfection and sterilization, etc. In this paper, the discharge characteristics are presented for the rf APGD plasmas generated with pure argon or argon-ethanol mixture as the plasma-forming gas and using water-cooled, bare copper electrodes. The experimental results show that the breakdown voltage can be reduced significantly when a small amount of ethanol is added into argon, probably due to the fact that the Penning ionization process is involved, and a pure α-mode discharge can be produced more easily with the help of ethanol. The uniformity of the rf APGDs of pure argon or argon-ethanol mixtures using bare metallic electrodes is identified with the aid of the intensified charge coupled device images.

  3. Numerical Study on Characteristics of Argon Radio-Frequency Glow Discharge with Varying gas Pressure

    Institute of Scientific and Technical Information of China (English)

    YU Qian; DENG Yong-Feng; LIU Yue; HAN Xian-Wei

    2008-01-01

    A one-dimensional fluid simulation on argon rf glow discharge with varying linearly gas pressure from 1 Torr to 100 Torr is performed. The model based on mass conservation equations for electron and ion under diffusion and mobility approximation, and the electron energy conservation equation is solved numerically by finite volume method. The numerical results show that a uniform plasma with high density can be obtained from rf glow discharge with varying gas pressure, and the density of plasma becomes higher as the gas pressure varies from 1 Torr to 100 Torr. It is also shown that in the range of the gas pressure from 1 Torr to 100 Torr with the slower rate of varying gas pressure, higher density of plasma can be obtained.

  4. Hybrid modeling of a capacitively coupled radio frequency glow discharge in argon: Combined Monte Carlo and fluid model

    NARCIS (Netherlands)

    Bogaerts, A.; Gijbels, R.; W. Goedheer,

    1999-01-01

    A hybrid model has been developed for a capacitively coupled rf glow discharge in argon, employed as a spectroscopic source in the field of analytical chemistry. The cell is a rather small cylinder with a very small rf-powered electrode (only 5 mm in diameter). The typical working conditions applied

  5. Influence of oxygen traces on an atmospheric-pressure radio-frequency capacitive argon plasma discharge

    International Nuclear Information System (INIS)

    An atmospheric-pressure capacitive discharge source driven by radio-frequency power supply at 13.56 MHz has been developed experimentally that is capable of producing a homogeneous and cold glow discharge in O2/Ar. With respect to the influence of oxygen component when diluted into argon plasma discharge on the discharge characteristics, the measurements of the electrical parameters (impedance, phase angle, resistance, and reactance) are made systematically and the densities of the metastable and resonant state of argon are determined by means of optical emission spectroscopy (OES). It is shown that the admixture of oxygen into argon plasma not only changes the electric characteristics but also alters the optical emission spectra greatly due to strong interaction between the oxygen content and the argon in the plasma environment.

  6. Radio frequency glow discharge-induced acidification of fluoropolymers.

    Science.gov (United States)

    Krawczyk, Benjamin M; Baltrusaitis, Jonas; Yoder, Colin M; Vargo, Terrence G; Bowden, Ned B; Kader, Khalid N

    2011-12-01

    Fluoropolymer surfaces are unique in view of the fact that they are quite inert, have low surface energies, and possess high thermal stabilities. Attempts to modify fluoropolymer surfaces have met with difficulties in that it is difficult to control the modification to maintain bulk characteristics of the polymer. In a previously described method, the replacement of a small fraction of surface fluorine by acid groups through radio frequency glow discharge created a surface with unexpected reactivity allowing for attachment of proteins in their active states. The present study demonstrates that 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride (EDC) reacts with the acid groups on fluoropolymer surfaces in a novel reaction not previously described. This reaction yields an excellent leaving group in which a primary amine on proteins can substitute to form a covalent bond between a protein and these surfaces. In an earlier study, we demonstrated that collagen IV could be deposited on a modified PTFE surface using EDC as a linker. Once collagen IV is attached to the surface, it assembles to form a functional stratum resembling collagen IV in native basement membrane. In this study, we show data suggesting that the fluorine to carbon ratio determines the acidity of the fluoropolymer surfaces and how well collagen IV attaches to and assembles on four different fluoropolymer surfaces. PMID:21887736

  7. Endotoxin removal by radio frequency gas plasma (glow discharge)

    Science.gov (United States)

    Poon, Angela

    2011-12-01

    Contaminants remaining on implantable medical devices, even following sterilization, include dangerous fever-causing residues of the outer lipopolysaccharide-rich membranes of Gram-negative bacteria such as the common gut microorganism E. coli. The conventional method for endotoxin removal is by Food & Drug Administration (FDA)-recommended dry-heat depyrogenation at 250°C for at least 45 minutes, an excessively time-consuming high-temperature technique not suitable for low-melting or heat-distortable biomaterials. This investigation evaluated the mechanism by which E. coli endotoxin contamination can be eliminated from surfaces during ambient temperature single 3-minute to cumulative 15-minute exposures to radio-frequency glow discharge (RFGD)-generated residual room air plasmas activated at 0.1-0.2 torr in a 35MHz electrodeless chamber. The main analytical technique for retained pyrogenic bio-activity was the Kinetic Chromogenic Limulus Amebocyte Lysate (LAL) Assay, sufficiently sensitive to document compliance with FDA-required Endotoxin Unit (EU) titers less than 20 EU per medical device by optical detection of enzymatic color development corresponding to sterile water extracts of each device. The main analytical technique for identification of chemical compositions, amounts, and changes during sequential reference Endotoxin additions and subsequent RFGD-treatment removals from infrared (IR)-transparent germanium (Ge) prisms was Multiple Attenuated Internal Reflection (MAIR) infrared spectroscopy sensitive to even monolayer amounts of retained bio-contaminant. KimaxRTM 60 mm x 15 mm and 50mm x 15mm laboratory glass dishes and germanium internal reflection prisms were inoculated with E. coli bacterial endotoxin water suspensions at increments of 0.005, 0.05, 0.5, and 5 EU, and characterized by MAIR-IR spectroscopy of the dried residues on the Ge prisms and LAL Assay of sterile water extracts from both glass and Ge specimens. The Ge prism MAIR-IR measurements

  8. Endotoxin removal by radio frequency gas plasma (glow discharge)

    Science.gov (United States)

    Poon, Angela

    2011-12-01

    Contaminants remaining on implantable medical devices, even following sterilization, include dangerous fever-causing residues of the outer lipopolysaccharide-rich membranes of Gram-negative bacteria such as the common gut microorganism E. coli. The conventional method for endotoxin removal is by Food & Drug Administration (FDA)-recommended dry-heat depyrogenation at 250°C for at least 45 minutes, an excessively time-consuming high-temperature technique not suitable for low-melting or heat-distortable biomaterials. This investigation evaluated the mechanism by which E. coli endotoxin contamination can be eliminated from surfaces during ambient temperature single 3-minute to cumulative 15-minute exposures to radio-frequency glow discharge (RFGD)-generated residual room air plasmas activated at 0.1-0.2 torr in a 35MHz electrodeless chamber. The main analytical technique for retained pyrogenic bio-activity was the Kinetic Chromogenic Limulus Amebocyte Lysate (LAL) Assay, sufficiently sensitive to document compliance with FDA-required Endotoxin Unit (EU) titers less than 20 EU per medical device by optical detection of enzymatic color development corresponding to contaminant. KimaxRTM 60 mm x 15 mm and 50mm x 15mm laboratory glass dishes and germanium internal reflection prisms were inoculated with E. coli bacterial endotoxin water suspensions at increments of 0.005, 0.05, 0.5, and 5 EU, and characterized by MAIR-IR spectroscopy of the dried residues on the Ge prisms and LAL Assay of sterile water extracts from both glass and Ge specimens. The Ge prism MAIR-IR measurements were repeated after employing 3-minute RFGD treatments sequentially for more than 10 cycles to observe removal of deposited matter that correlated with diminished EU titers. The results showed that 5 cycles, for a total exposure time of 15 minutes to low-temperature gas plasma, was sufficient to reduce endotoxin titers to below 0.05 EU/ml, and correlated with concurrent reduction of major endotoxin

  9. Discharge characteristics of a radio-frequency capacitively coupled Ar/O2 glow discharge at atmospheric pressure

    International Nuclear Information System (INIS)

    In this study, the discharge characteristics of the developed atmospheric pressure homogeneous and cold plasma source in Ar/O2 glow discharge driven by radio-frequency (13.56 MHz) are investigated experimentally by means of electric measurements. The electron density is estimated to be in the order of 1011 cm-3 in the abnormal discharge regime and is reduced by half in amount when the oxygen is mixed into argon plasma at oxygen-to-argon ratio of 0.3 and 0.6 vol.% at the same input power. The estimated electron temperature assumes the value of 1.4 eV in the abnormal discharge regime and the addition of oxygen to the argon plasma at the oxygen-to-argon ratio smaller than 1.0 vol.% does not alter the electron temperature appreciably.

  10. Gas Breakdown of Radio Frequency Glow Discharges in Helium at near Atmospheric Pressure

    Science.gov (United States)

    Liu, Xinkun; Xu, Jinzhou; Cui, Tongfei; Guo, Ying; Zhang, Jing; Shi, Jianjun

    2013-07-01

    A one-dimensional self-consistent fluid model was developed for radio frequency glow discharge in helium at near atmospheric pressure, and was employed to study the gas breakdown characteristics in terms of breakdown voltage. The effective secondary electron emission coefficient and the effective electric field for ions were demonstrated to be important for determining the breakdown voltage of radio frequency glow discharge at near atmospheric pressure. The constant of A was estimated to be 64±4 cm-1Torr-1, which was proportional to the first Townsend coefficient and could be employed to evaluate the gas breakdown voltage. The reduction in the breakdown voltage of radio frequency glow discharge with excitation frequency was studied and attributed to the electron trapping effect in the discharge gap.

  11. Decomposition of polychlorinated biphenyls (PCB's) in a radio-frequency glow discharge plasma

    International Nuclear Information System (INIS)

    A study was made on the decomposition of PCB's in a radio-frequency glow discharge plasma. When PCB's were decomposed in a plasma of oxygen at a few Torr, they were completely decomposed to gaseous products: carbon monoxide, carbon dioxide, water, hydrogen chloride, chlorine, and chlorine dioxide. Hazardous compounds such as phosgene and vinyl chloride were not detected by a GC-MS analysis. (author)

  12. Genetic effects of radio-frequency, atmospheric-pressure glow discharges with helium

    International Nuclear Information System (INIS)

    Due to low gas temperatures and high densities of active species, atmospheric-pressure glow discharges (APGDs) would have potential applications in the fields of plasma-based sterilization, gene mutation, etc. In this letter, the genetic effects of helium radio-frequency APGD plasmas with the plasmid DNA and oligonucleotide as the treated biomaterials are presented. The experimental results show that it is the chemically active species, instead of heat, ultraviolet radiation, intense electric field, and/or charged particles, that break the double chains of the plasmid DNA. The genetic effects depend on the plasma operating parameters, e.g., power input, helium flow rate, processing distance, time, etc

  13. Genetic effects of radio-frequency, atmospheric-pressure glow discharges with helium

    Science.gov (United States)

    Li, Guo; Li, He-Ping; Wang, Li-Yan; Wang, Sen; Zhao, Hong-Xin; Sun, Wen-Ting; Xing, Xin-Hui; Bao, Cheng-Yu

    2008-06-01

    Due to low gas temperatures and high densities of active species, atmospheric-pressure glow discharges (APGDs) would have potential applications in the fields of plasma-based sterilization, gene mutation, etc. In this letter, the genetic effects of helium radio-frequency APGD plasmas with the plasmid DNA and oligonucleotide as the treated biomaterials are presented. The experimental results show that it is the chemically active species, instead of heat, ultraviolet radiation, intense electric field, and/or charged particles, that break the double chains of the plasmid DNA. The genetic effects depend on the plasma operating parameters, e.g., power input, helium flow rate, processing distance, time, etc.

  14. Atmospheric Pressure Radio Frequency Dielectric Barrier Discharges in Nitrogen/Argon

    International Nuclear Information System (INIS)

    This work reports the experimental results on the characteristics of radio frequency dielectric barrier N2/Ar discharges. Depending on the nitrogen content in the feed gas and the input power, the discharge can operate in two different modes: a homogeneous glow discharge and a constricted discharge. With increasing input power, the number of discharge columns increases. The discharge columns have starlike structures and exhibit symmetric self-organized arrangement. Optical emission spectroscopy was performed to estimate the plasma temperature. Spatially resolved gas temperature measurements, determined from NO emission rotational spectroscopy were taken across the 4.4 mm gap filled by the discharge. Gas temperature in the middle of the gas gap is lower than that close to the electrodes

  15. Enhanced tissue integration of implantable electrodes for sensing, and stimulation, via radio frequency glow discharge

    Science.gov (United States)

    O'Connor, Laurie M.

    Biopotential electrodes are conductive materials that convert electronic currents to or from ionic currents for sensing, and stimulating specific tissue sites for medical applications. Implanted electrodes become "walled off" by the foreign body tissue reactions producing poorly attached scar capsules dominated by surrounding dense collagenous lamellae and source fibroblasts which are electrically resistive. The conductive interstitial fluid that is typical between an electrode and the resistive capsule allows spurious current paths. The insulating layer increases the distance between the electrode and the target sites and poor attachment often results in electrode migration within the host tissue. This investigation tested the hypothesis that surface-energy modulation of electrodes, via Radio Frequency Glow Discharge Treatment (RFGDT), can improve the performance of tissue-implantable electrodes by reducing the foreign body tissue reaction and enhancing interfacial bonding between the tissue and electrode material. Previously published findings were reproduced in a pilot study of explanted reference grade medical-grade methyl silicone (PDMS) and commercially pure titanium (cpTi) materials and their tissue capsules from 30-day subcutaneous exposures in Balb/C mice. The low-critical surface tension PDMS produced thick, dense, poorly attached scar capsules while the higher-surface-energy commercially pure titanium (cpTi) produced more cellular and strongly attached tissue layers difficult to delaminate from the biomaterial. For the main body of work, cpTi, capacitor-grade Tantalum (Ta), and synthetic heart valve-quality Pyrolytic Carbon (PyC) were evaluated, representative of potential high-surface-energy implant electrode materials. Their surface characteristics were determined as-manufactured and after Radio Frequency Glow Discharge Treatment (RFGDT) by Critical Surface Tension (CST) measurement, Scanning Electron Microscopy (SEM), Energy Dispersive X

  16. Numerical simulation of the sustaining discharge in radio frequency hollow cathode discharge in argon

    International Nuclear Information System (INIS)

    In this paper, a two-dimensional fluid model was developed to study the radio frequency (RF) hollow cathode discharge (HCD) in argon at 1 Torr. The evolutions of the particle density distribution and the ionization rate distribution in RF HCD at 13.56 MHz indicate that the discharge mainly occurs inside the hollow cathode. The spatio-temporal distributions of the ionization rate and the power deposition within the hollow cathode imply that sheath oscillation heating is the primary mechanism to sustain the RF HCD, whereas secondary electron emission plays a negligible role. However, as driving frequency decreases, secondary electron heating becomes a dominant mechanism to sustain the discharge in RF hollow cathode

  17. Sampling modulation technique in radio-frequency helium glow discharge emission source by use of pulsed laser ablation.

    Science.gov (United States)

    Naeem, Tariq Mahmood; Matsuta, Hideyuki; Wagatsuma, Kazuaki

    2004-05-01

    An emission excitation source comprising a high-frequency diode-pumped Q-switched Nd:YAG laser and a radio-frequency powered glow discharge lamp is proposed. In this system sample atoms ablated by the laser irradiation are introduced into the lamp chamber and subsequently excited by the helium glow discharge plasma. The pulsed operation of the laser can produce a cyclic variation in the emission intensities of the sample atoms whereas the plasma gas species emit the radiation continuously. The salient feature of the proposed technique is the selective detection of the laser modulation signal from the rest of the continuous background emissions, which can be achieved with the phase sensitive detection of the lock-in amplifier. The arrangement may be used to estimate the emission intensity of the laser ablated atom, free from the interference of other species present in the plasma. The experiments were conducted with a 13.56 MHz radio-frequency (rf) generator operated at 80 W power to produce plasma and the laser at a wavelength of 1064 nm (pulse duration:34 ns, repetition rate:7 kHz and average pulse energy of about 0.36 mJ) was employed for sample ablation. The measurements resulted in almost complete removal of nitrogen molecular bands (N(2)(+) 391.44 nm). Considerable reduction (about 75%) in the emission intensity of a carbon atomic line (C I 193.03 nm) was also observed. PMID:15034707

  18. Spatially resolved Langmuir probe diagnostics in a capacitively coupled radio frequency argon and oxygen plasma

    International Nuclear Information System (INIS)

    Axial and radial profiles of the positive ion saturation current were measured by Langmuir probe diagnostics in a capacitively coupled radio frequency (RF) plasma in argon and oxygen. Under certain conditions these profiles provide the spatial density distribution of the positive ions, which corresponds approximately to the electron density in the electropositive plasma. Particularly in oxygen at low RF power a peak in the ion saturation current appears in the radial direction at the electrode boundary. The axial position s at the maximum ion saturation current depends on total pressure with s ∝ p−1/3, which reveals the pressure dependence of a collisional RF sheath. Furthermore, Langmuir probe characteristics were evaluated in terms of the Druyvesteyn method to determine the radial behavior of the electron energy probability function (EEPF). From the EEPF the radially resolved effective electron temperature and electron density were calculated. The radial electron density profile from the Langmuir probe was numerically integrated to calculate a line integrated electron density for comparison with the measured line integrated density from 160 GHz microwave interferometry. The integration over the Langmuir probe density results in a line integrated density, which amounts to 40% of the line integrated density from microwave interferometry. (paper)

  19. Nitrogen Removal from Molten Steel under Argon DC Glow Plasma

    Institute of Scientific and Technical Information of China (English)

    SUN Ming-shan; DING Wei-zhong; LU Xiong-gang

    2005-01-01

    Under argon DC glow plasma, the nitrogen removal from molten steel was studied. The experimental result showed that nitrogen mass percent could be reduced to 0.000 8%. The change of polarity had no impact on nitrogen removal when the nitrogen mass percent was low. The mechanism of denitrogenation of molten steel under argon DC glow plasma was discussed.

  20. Nitrogen and argon doping of niobium for superconducting radio frequency cavities: a pathway to highly efficient accelerating structures

    OpenAIRE

    Grassellino, A.; Romanenko, A.; Melnychuk, O.; Trenikhina, Y.; Crawford, A; Rowe, A.; Wong, M; Sergatskov, D.; Khabiboulline, T.; Barkov, F.

    2013-01-01

    We report a surface treatment that systematically improves the quality factor of niobium radio frequency cavities beyond the expected limit for niobium. A combination of annealing in a partial pressure of nitrogen or argon gas and subsequent electropolishing of the niobium cavity surface leads to unprecedented low values of the microwave surface resistance, and an improvement in the efficiency of the accelerating structures up to a factor of 3, reducing the cryogenic load of superconducting c...

  1. Pulsed RF discharges, glow and filamentary mode at atmospheric pressure in argon

    International Nuclear Information System (INIS)

    The properties of a pulsed radio frequency capacitive discharge are investigated at atmospheric pressure in argon. The discharge can operate in two different modes: a homogeneous glow discharge or turn into filaments. By pulsing the 13.56 MHz generator both the filamentary and the glow modes can be selected depending on the pulse width and period. For a 5 μs pulse width (∼70 RF cycles in the pulse), short pulse periods (less than 100 μs) result in a filamentary discharge while long pulse periods (greater than 1 ms) result in a glow discharge. Optical emission spectroscopy and power measurements were performed to estimate the plasma temperature and density. Water vapour was introduced to the discharge as a source of hydrogen and the Stark broadening of the Balmer Hβ line was measured to allow the plasma density to be estimated as 1015 cm-3 in the filamentary mode. The estimation of the glow mode density was based on power balance and yielded a density of 5 x 1011 cm-3. Emission line ratio measurements coupled with the Saha equation resulted in an estimate of electron temperature of approximatively 1.3 eV for the glow mode and 1.7 eV for the filaments. Using the glow mode at a duty cycle of 10% is effective in decreasing the hydrophobicity of polymer films while keeping the temperature low

  2. Production of nanometric particles in radio frequency glow discharges in mixtures of silane and methane

    OpenAIRE

    Bertrán Serra, Enric; Costa i Balanzat, Josep; Viera Mármol, Gregorio; Zhang, R. Q.

    1996-01-01

    The formation of silicon particles in rf glow discharges has attracted attention due to their effect as a contaminant during film deposition or etching. However, silicon and silicon alloy powders produced by plasma¿enhanced chemical vapor deposition (PECVD) are promising new materials for sintering ceramics, for making nanoscale filters, or for supporting catalytic surfaces. Common characteristics of these powders are their high purity and the easy control of their stoichiometry through the c...

  3. Radio frequency atmospheric pressure glow discharge in α and γ modes between two coaxial electrodes

    Science.gov (United States)

    Shang, Wanli; Wang, Dezhen; Zhang, Yuantao

    2008-09-01

    The discharge in pure helium and the influence of small nitrogen impurities at atmospheric pressure are investigated based on a one-dimensional self-consistent fluid model controlled by a dielectric barrier between two coaxial electrodes. The simulation of the radiofrequency (rf) discharge is based on the one-dimensional continuity equations for electrons, ions, metastable atoms, and molecules, with the much simpler current conservation law replacing the Poisson equation for electric field. Through a computational study of rf atmospheric glow discharges over a wide range of current density, this paper presents evidence of at least two glow discharge modes, namely the α mode and the γ mode. The simulation results show the asymmetry of the discharge set exercises great influence on the discharge mechanisms compared to that with parallel-plane electrodes. It is shown that the particle densities are not uniform in the discharge region but increase gradually from the outer to the inner electrode in both modes. The contrasting dynamic behaviors of the two glow modes are studied. Secondary electron emission strongly influences gas ionization in the γ mode yet matters little in the α mode.

  4. Effect of discharge parameters on emission yields in a radio-frequency glow-discharge atomic-emission source

    Science.gov (United States)

    Parker, Mark; Hartenstein, Matthew L.; Marcus, R. Kenneth

    1997-05-01

    A study is performed on a radio-frequency glow-discharge atomic-emission (rf-GD-AES) source to determine the factors effecting the emission yields for both metallic and nonconductive sample types. Specifically, these studies focus on determining how the operating parameters (power and pressure) influence emission yields. The results follow predicted patterns as determined by Langmuir probe diagnostic studies of a similar source. In particular, discharge gas pressure is the key operating parameter as slight changes in pressure may significantly affect the emission yield of the analyte species. RF power is less important and is shown to produce only relatively small changes in the emission yield over the ranges typically used in rf-GD analyses. These studies indicate that the quantitative analysis of layered materials, depth-profiling, may be adversely affected if the data collection scheme, i.e. the quantitative algorithm, requires changing the pressure during an analysis to keep the operating current and voltage constant. A direct relationship is shown to exist between the Ar (discharge gas) emission intensity and that of sputtered species for nonconductors. This observance is used to compensate for differences in emission intensities observed in the analysis of various thickness nonconductive samples. The sputtered element emission signals are corrected based on the emission intensity of an Ar (1) transition, implying that quantitative analysis of nonconductive samples is not severely limited by the availability of matrix matched standards.

  5. Development of radio-frequency-powered helium glow discharge optical emission source associated with sampling by laser ablation

    International Nuclear Information System (INIS)

    A new excitation source for emission spectrometry consisting of an r.f-powered helium glow discharge plasma and a laser-diode pumped Q-switched Nd:YAG laser, was developed. The Nd:YAG laser works dominantly as a sampling source for introduction of sample atoms to the glow discharge plasma, because the laser induced plasma cannot be generated by the laser itself due to its high repetition rate. On the other hand, the helium glow discharge plasma mainly acts as excitation source, because little amounts od sample atoms can be introduced due to the low sputtering rate. This effect arises from the low sputtering yield as well as the low ionization efficiency of helium atom. Besides, the excited species of helium gases has the excitation ability for atomic species requiring large excitation energies as fluorine atom due to their high metastable levels. From these characteristics in this method, the sampling process and the excitation having high excitation energy levels. In this study, fluorine atomic lines requiring large excitation energies were measured. These lines were observed only when the laser was irradiated to the helium plasma. They could be observed neither in the argon plasma nor in the helium plasma without the laser irradiation. Further, the calibration curve for a fluorine atomic line gave a linear relationship in the LiF concentration range of 0.02-5.0 mass%, as shown in Fig 2.

  6. Electron properties and air mixing in radio frequency driven argon plasma jets at atmospheric pressure

    International Nuclear Information System (INIS)

    A time modulated radio frequency (RF) plasma jet operated with an Ar mixture is investigated by measuring the electron density and electron temperature using Thomson scattering. The measurements have been performed spatially resolved for two different electrode configurations and as a function of the plasma dissipated power and air concentration admixed to the Ar. Time resolved measurements of electron densities and temperatures during the RF cycle and after plasma power switch-off are presented. Furthermore, the influence of the plasma on the air entrainment into the effluent is studied using Raman scattering

  7. Spectroscopic characterization of a radio-frequency argon plasma jet discharge in ambient air

    Science.gov (United States)

    Cullen, P. J.; Milosavljević, V.

    2015-06-01

    This study includes a detailed experimental investigation of the spatial and temporal spectroscopic emission of an argon plasma jet discharge. The study is carried out in ambient air and quenching by inflowing air species is considered. The optical emission spectroscopy of neutral atomic spectral lines and molecular bands, over a range of plasma process parameters, is investigated. Wavelength-resolved argon optical emission profiles are used to monitor the electron energy distribution function and the density of argon metastable atoms. The experimental data indicates that the argon flow rate, in a confined open-air plasma discharge, limits the impact of molecular oxygen in the creation of oxygen radicals. The absolute calibrated emission spectra facilitate the possibility of standardization of the so-called plasma dose.

  8. Spectroscopic Characterization of a Radio-Frequency Argon Plasma Jet Discharge in Ambient Air

    OpenAIRE

    Cullen, Patrick; Milosavljevic, Vladimir

    2015-01-01

    This study includes a detailed experimental investigation of the spatial and temporal spectroscopic emission of an argon plasma jet discharge. The study is carried out in ambient air and quenching by inflowing air species is considered. The optical emission spectroscopy of neutral atomic spectral lines and molecular bands, over a range of plasma process parameters, is investigated. Wavelength-resolved argon optical emission profiles are used to monitor the electron energy distribution functio...

  9. Surface modification of polypropylene (PP) using single and dual high radio frequency capacitive coupled argon plasma discharge

    Science.gov (United States)

    Akbar, D.

    2016-01-01

    Single (40.68 MHz) and dual (40.68/2.1 MHz) high radio frequency (RF) argon plasma discharge was employed as a source of a low-temperature treatment mechanism that was used to modify the surface of polypropylene (PP). The effects of argon plasma on the surface chemistry and the surface morphology of PP were studied using X-ray diffraction analyses. In this study, samples were treated under different plasma operation conditions for parameters such as RF power, gas pressure and treatment time. Furthermore, the crystallite size was calculated (using Scherrer equation) from the diffraction pattern of the β fraction (Full Width at Half maximum) for PP samples. The results reveal that the crystallite size strongly increases with RF power and treatment time, but decreases with gas pressure. From the analysis, it was found that the treated samples have higher crystallite sizes in compared to those of the single RF plasma discharge. This happens because the increase of plasma temperature leads to increases in the crystallization of PP sample, so that the crystallite size also increases. Furthermore, because of the advantageous features of the dual-RF plasma mode, the surface modification of PP sample can occur more quickly than is possible via the single-RF plasma discharge.

  10. Effect of neutral gas heating in argon radio frequency inductively coupled plasma

    International Nuclear Information System (INIS)

    Heating of neutral gas in inductively coupled plasma (ICP) is known to result in neutral gas depletion. In this work, this effect is considered in the simulation of the magnetic field distribution of a 13.56 MHz planar coil ICP. Measured electron temperatures and densities at argon pressures of 0.03, 0.07 and 0.2 mbar were used in the simulation whilst neutral gas temperatures were heuristically fitted. The simulated results showed reasonable agreement with the measured magnetic field profile. (author)

  11. Paschen law for argon glow discharge

    International Nuclear Information System (INIS)

    Electric discharge between two electrically charged surfaces occurs at a well-defined, gas-dependent combination of atmospheric pressure and the distance between those surfaces, as described by Paschen's law. The understanding of when the discharge will occur in an Ar discharge is essential basic knowledge. A glow discharge apparatus was used in this experiment of Ar discharge at a pressure range between 2.0 Torr and 12 Torr, a power of 20 W and 40 l/min flow rate of gases. The optical emission spectroscopy was carried out in the wavelength range of 200 to 1100 nm. Here, we present experimentally measured plasma Paschen curves for Ar gas and compare our results of breakdown voltages with the literature. The minimum voltage measured for a discharge in Ar atmosphere was 215 ± 2.2 at 0.7 Torr-cm, which agree with previous measurements.

  12. Two-dimensional profile measurement of plasma parameters in radio frequency-driven argon atmospheric pressure plasma jet

    Energy Technology Data Exchange (ETDEWEB)

    Seo, B. H.; Kim, J. H., E-mail: jhkim86@kriss.re.kr [Center for Vacuum Technology, Korea Research Institute of Standards and Science, Daejeon 305-340 (Korea, Republic of); Kim, D. W. [Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-338 (Korea, Republic of); You, S. J., E-mail: sjyou@cnu.ac.kr [Department of Physics, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

    2015-09-15

    The two-dimensional profiles of the electron density, electron temperature, neutral translational temperature, and molecular rotational temperature are investigated in an argon atmospheric pressure plasma jet, which is driven by the radio frequency of 13.56 MHz by means of the laser scattering methods of Thomson, Rayleigh, and Raman. All measured parameters have maximum values at the center of the discharge and decrease toward the plasma edge. The results for the electron temperature profile are contrary to the results for the microwave-driven plasma. From our experimental results, the profiles of the plasma parameters arise from the radial contraction of plasmas and the time averaged profile of the electric field, which is obtained by a microwave simulation performed under identical conditions to the plasma jet. In the case of the neutral temperature, a higher translational temperature than the rotational temperature is measured, and its discrepancy is tentatively explained in terms of the low ion-neutral charge exchange rate and the additional degrees of freedom of the molecules. The description of our experimental results and the underlying physics are addressed in detail.

  13. A hybrid model of radio frequency biased inductively coupled plasma discharges: description of model and experimental validation in argon

    Science.gov (United States)

    Wen, De-Qi; Liu, Wei; Gao, Fei; Lieberman, M. A.; Wang, You-Nian

    2016-08-01

    A hybrid model, i.e. a global model coupled bidirectionally with a parallel Monte-Carlo collision (MCC) sheath model, is developed to investigate an inductively coupled discharge with a bias source. This hybrid model can self-consistently reveal the interaction between the bulk plasma and the radio frequency (rf) bias sheath. More specifically, the plasma parameters affecting characteristics of rf bias sheath (sheath length and self-bias) are calculated by a global model and the effect of the rf bias sheath on the bulk plasma is determined by the voltage drop of the rf bias sheath. Moreover, specific numbers of ions are tracked in the rf bias sheath and ultimately the ion energy distribution function (IEDF) incident on the bias electrode is obtained. To validate this model, both bulk plasma density and IEDF on the bias electrode in an argon discharge are compared with experimental measurements, and a good agreement is obtained. The advantage of this model is that it can quickly calculate the bulk plasma density and IEDF on the bias electrode, which are of practical interest in industrial plasma processing, and the model could be easily extended to serve for industrial gases.

  14. Two-dimensional profile measurement of plasma parameters in radio frequency-driven argon atmospheric pressure plasma jet

    International Nuclear Information System (INIS)

    The two-dimensional profiles of the electron density, electron temperature, neutral translational temperature, and molecular rotational temperature are investigated in an argon atmospheric pressure plasma jet, which is driven by the radio frequency of 13.56 MHz by means of the laser scattering methods of Thomson, Rayleigh, and Raman. All measured parameters have maximum values at the center of the discharge and decrease toward the plasma edge. The results for the electron temperature profile are contrary to the results for the microwave-driven plasma. From our experimental results, the profiles of the plasma parameters arise from the radial contraction of plasmas and the time averaged profile of the electric field, which is obtained by a microwave simulation performed under identical conditions to the plasma jet. In the case of the neutral temperature, a higher translational temperature than the rotational temperature is measured, and its discrepancy is tentatively explained in terms of the low ion-neutral charge exchange rate and the additional degrees of freedom of the molecules. The description of our experimental results and the underlying physics are addressed in detail

  15. Influence of longitudinal argon flow on DC glow discharge at atmospheric pressure

    Science.gov (United States)

    Zhu, Sha; Jiang, Weiman; Tang, Jie; Xu, Yonggang; Wang, Yishan; Zhao, Wei; Duan, Yixiang

    2016-05-01

    A one-dimensional self-consistent fluid model was employed to investigate the influence of longitudinal argon flow on the DC glow discharge at atmospheric pressure. It is found that the charges exhibit distinct dynamic behaviors at different argon flow velocities, accompanied by a considerable change in the discharge structure. The positive argon flow allows for the reduction of charge densities in the positive column and negative glow regions, and even leads to the disappearance of negative glow. The negative argon flow gives rise to the enhancement of charge densities in the positive column and negative glow regions. These observations are attributed to the fact that the gas flow convection influences the transport of charges through different manners by comparing the argon flow velocity with the ion drift velocity. The findings are important for improving the chemical activity and work efficiency of the plasma source by controlling the gas flow in practical applications.

  16. Optical Emission Analysis of a Si(CH3)4-Argon Radio Frequency Plasma for SiC Films Deposition

    OpenAIRE

    Andrieux, M.; Badie, J.; Bisch, C.; Ducarroir, M.; Teyssandier, F.

    1995-01-01

    RF glow discharges from tetramethylsilane diluted in an argon flow have been investigated in a cold wall R.F. (2MHz) P.E.C.V.D. reactor. This reactor is used for fast deposition of adherent amorphous silicon carbide films (with Si/C≈1.2) on steel. Optical emission from the plasma was sampled using a high resolution double monochromator (2m focal length, 1800 grooves/mm) coupled with a multichannel CCD detector. Only the lines corresponding to neutral or ionised Argon (Ar, Ar+), the broadened ...

  17. The back-diffusion effect of air on the discharge characteristics of atmospheric-pressure radio-frequency glow discharges using bare metal electrodes

    International Nuclear Information System (INIS)

    Radio-frequency (RF), atmospheric-pressure glow discharge (APGD) plasmas using bare metal electrodes have promising prospects in the fields of plasma-aided etching, deposition, surface treatment, disinfection, sterilization, etc. In this paper, the discharge characteristics, including the breakdown voltage and the discharge voltage for sustaining a stable and uniform α mode discharge of the RF APGD plasmas are presented. The experiments are conducted by placing the home-made planar-type plasma generator in ambient and in a vacuum chamber, respectively, with helium as the primary plasma-forming gas. When the discharge processes occur in ambient, particularly for the lower plasma-working gas flow rates, the experimental measurements show that it is the back-diffusion effect of air in atmosphere, instead of the flow rate of the gas, that results in the obvious decrease in the breakdown voltage with increasing plasma-working gas flow rate. Further studies on the discharge characteristics, e.g. the luminous structures, the concentrations and distributions of chemically active species in plasmas, with different plasma-working gases or gas mixtures need to be conducted in future work

  18. The back-diffusion effect of air on the discharge characteristics of atmospheric-pressure radio-frequency glow discharges using bare metal electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Sun Wenting; Liang Tianran; Wang Huabo; Li Heping; Bao Chengyu [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China)

    2007-05-15

    Radio-frequency (RF), atmospheric-pressure glow discharge (APGD) plasmas using bare metal electrodes have promising prospects in the fields of plasma-aided etching, deposition, surface treatment, disinfection, sterilization, etc. In this paper, the discharge characteristics, including the breakdown voltage and the discharge voltage for sustaining a stable and uniform {alpha} mode discharge of the RF APGD plasmas are presented. The experiments are conducted by placing the home-made planar-type plasma generator in ambient and in a vacuum chamber, respectively, with helium as the primary plasma-forming gas. When the discharge processes occur in ambient, particularly for the lower plasma-working gas flow rates, the experimental measurements show that it is the back-diffusion effect of air in atmosphere, instead of the flow rate of the gas, that results in the obvious decrease in the breakdown voltage with increasing plasma-working gas flow rate. Further studies on the discharge characteristics, e.g. the luminous structures, the concentrations and distributions of chemically active species in plasmas, with different plasma-working gases or gas mixtures need to be conducted in future work.

  19. The back-diffusion effect of air on the discharge characteristics of atmospheric-pressure radio-frequency glow discharges using bare metal electrodes

    Science.gov (United States)

    Sun, Wen-Ting; Liang, Tian-Ran; Wang, Hua-Bo; Li, He-Ping; Bao, Cheng-Yu

    2007-05-01

    Radio-frequency (RF), atmospheric-pressure glow discharge (APGD) plasmas using bare metal electrodes have promising prospects in the fields of plasma-aided etching, deposition, surface treatment, disinfection, sterilization, etc. In this paper, the discharge characteristics, including the breakdown voltage and the discharge voltage for sustaining a stable and uniform α mode discharge of the RF APGD plasmas are presented. The experiments are conducted by placing the home-made planar-type plasma generator in ambient and in a vacuum chamber, respectively, with helium as the primary plasma-forming gas. When the discharge processes occur in ambient, particularly for the lower plasma-working gas flow rates, the experimental measurements show that it is the back-diffusion effect of air in atmosphere, instead of the flow rate of the gas, that results in the obvious decrease in the breakdown voltage with increasing plasma-working gas flow rate. Further studies on the discharge characteristics, e.g. the luminous structures, the concentrations and distributions of chemically active species in plasmas, with different plasma-working gases or gas mixtures need to be conducted in future work.

  20. Numerical Simulation of Hydrogen Dilution Effects on Deposition of Silicon Film at Atmospheric Pressure Radio-Frequency Argon Silane Plasma

    International Nuclear Information System (INIS)

    Based on the one-dimensional fluid model, the characteristics of homogeneous discharges with hydrogen diluted silane and argon at atmospheric pressure are numerically investigated. The primary processes of excitation and ionization and sixteen reactions of radicals with radicals in silane/hydrogen/argon discharges are considered. The effects of hydrogen dilution on the densities of species (e, H, SiH3+, SiH3-, SiH3,) are analyzed. The simulation results show that the highest densities of e, SiH3+, H, SiH3-, SiH3 correspond to the optimal dilution concentration of H2. The deposition rate of μc-Si:H film depends on the SiH3 concentration, and atomic hydrogen in the plasma is found to play an important role in the crystallization fraction of the deposited films. This model explains the effects of H2 dilution on the deposition rate and crystallized fraction of μc-Si:H film growth.

  1. Comparative study on contribution of charge-transfer collision to excitations of iron ion between argon radio-frequency inductively-coupled plasma and nitrogen microwave induced plasma

    Science.gov (United States)

    Satoh, Kozue; Wagatsuma, Kazuaki

    2015-06-01

    This paper describes an ionization/excitation phenomenon of singly-ionized iron occurring in an Okamoto-cavity microwave induced plasma (MIP) as well as an argon radio-frequency inductively-coupled plasma (ICP), by comparing the Boltzmann distribution among iron ionic lines (Fe II) having a wide range of the excitation energy from 4.76 to 9.01 eV. It indicated in both the plasmas that plots of Fe II lines having lower excitation energies (4.76 to 5.88 eV) were fitted on each linear relationship, implying that their excitations were caused by a dominant thermal process such as collision with energetic electron. However, Fe II lines having higher excitation energies (more than 7.55 eV) had a different behavior from each other. In the ICP, Boltzmann plots of Fe II lines assigned to the higher excited levels also followed the normal Boltzmann relationship among the low-lying excited levels, even including a deviation from it in particular excited levels having an excitation energy of ca. 7.8 eV. This deviation can be attributed to a charge-transfer collision with argon ion, which results in the overpopulation of these excited levels, but the contribution is small. On the other hand, the distribution of the high-lying excited levels was non-thermal in the Okamoto-cavity MIP, which did not follow the normal Boltzmann relationship among the low-lying excited levels. A probable reason for the non-thermal characteristics in the MIP is that a charge-transfer collision with nitrogen molecule ion having many vibrational/rotational levels could work for populating the 3d64p (3d54s4p) excited levels of iron ion broadly over an energy range of 7.6-9.0 eV, while collisional excitation by energetic electron would occur insufficiently to excite these high-energy levels.

  2. Silicon nanoparticle formation depending on the discharge conditions of an atmospheric radio-frequency driven microplasma with argon/silane/hydrogen gases

    International Nuclear Information System (INIS)

    Atmospheric radio-frequency driven non-equilibrium microplasma jets in an argon/silane/hydrogen gas mixture are characterised and analysed with respect to the reaction pathway, which leads to the formation of silicon nanoparticles. Optical emission spectroscopy is used to obtain initial information about possible plasma chemistry processes and high-time-resolution images uncover the mode of operation of the discharge. It is demonstrated that the effect of the way the electric field is applied (parallel or perpendicular to the gas flow), the gas flow magnitude, and varying the gas mixture can result in three different operation modes—filamentary plasma with a stationary filament, diffuse-like plasma with the filament changing its position, and a diffuse non-filamentary plasma—being formed in the one millimetre inner diameter tube with ring electrodes, which apply an electric field parallel to the gas flow (a parallel-field plasma). An electric field applied perpendicular to the gas flow (a cross-field plasma) results only in a homogeneous diffuse discharge with low plasma density. The nanoparticles synthesised in the microplasma jet are studied by scanning electron microscopy and dynamic light scattering. The experimental results reveal that the silane precursor can very probably be fully dissociated in the parallel-field plasma and particles with sizes almost independent of silane concentration are generated. In contrast, silane is only weakly fragmented in the cross-field plasma and negative ions are formed. Particle size reacts very sensitively to silane concentration in this case and is a result of a condensation of radicals or ions on the particle surface. (paper)

  3. Electrical and optical properties of radio frequency magnetron-sputtered lightly aluminum-doped zinc oxide thin films deposited in hydrogen–argon gas

    International Nuclear Information System (INIS)

    We studied the electrical and optical properties of lightly aluminum-doped zinc oxide (L-AZO) films, which were deposited on soda-lime glass substrates by radio frequency (RF) magnetron sputtering using a 0.2 wt.% aluminum-doped zinc oxide target and a 0.3 wt.% hydrogen-mixed argon (Ar/0.3% H2) gas. The L-AZO films were characterized in terms of structural, optical, and electrical properties by X-ray diffraction, ultraviolet–visible spectrophotometry, photoluminescence and Hall measurements at room temperature. The Al contents of the L-AZO film were analyzed with secondary ion mass spectroscopy. As the Ar/0.3%H2 gas flow was increased up to 200 sccm, the transmittance and conductivity of the film simultaneously improved as a function of the increasing flow rate without additional thermal or gas treatment. The 40 nm-thick L-AZO film, which was deposited by an Ar/0.3% H2 gas flow of 200 sccm at a substrate temperature of 100 °C, had a carrier concentration of 1.0 × 1020/cm3, resistivity of 5.5 × 10−3 Ω-cm, and an average transmittance of 93% in the wavelength range from 300 nm to 2000 nm. - Highlights: • Electrical and optical properties of lightly Al-doped ZnO (L-AZO) thin films. • Films studied under various deposition conditions. • Carrier concentration (CC) and transmittance for thickness > 100 nm is studied. • For thin L-AZO films, CC and transmittance depend on O vacancies and interstitial H atoms

  4. Comparative study on contribution of charge-transfer collision to excitations of iron ion between argon radio-frequency inductively-coupled plasma and nitrogen microwave induced plasma

    Energy Technology Data Exchange (ETDEWEB)

    Satoh, Kozue; Wagatsuma, Kazuaki, E-mail: wagatuma@imr.tohoku.ac.jp

    2015-06-01

    This paper describes an ionization/excitation phenomenon of singly-ionized iron occurring in an Okamoto-cavity microwave induced plasma (MIP) as well as an argon radio-frequency inductively-coupled plasma (ICP), by comparing the Boltzmann distribution among iron ionic lines (Fe II) having a wide range of the excitation energy from 4.76 to 9.01 eV. It indicated in both the plasmas that plots of Fe II lines having lower excitation energies (4.76 to 5.88 eV) were fitted on each linear relationship, implying that their excitations were caused by a dominant thermal process such as collision with energetic electron. However, Fe II lines having higher excitation energies (more than 7.55 eV) had a different behavior from each other. In the ICP, Boltzmann plots of Fe II lines assigned to the higher excited levels also followed the normal Boltzmann relationship among the low-lying excited levels, even including a deviation from it in particular excited levels having an excitation energy of ca. 7.8 eV. This deviation can be attributed to a charge-transfer collision with argon ion, which results in the overpopulation of these excited levels, but the contribution is small. On the other hand, the distribution of the high-lying excited levels was non-thermal in the Okamoto-cavity MIP, which did not follow the normal Boltzmann relationship among the low-lying excited levels. A probable reason for the non-thermal characteristics in the MIP is that a charge-transfer collision with nitrogen molecule ion having many vibrational/rotational levels could work for populating the 3d{sup 6}4p (3d{sup 5}4s4p) excited levels of iron ion broadly over an energy range of 7.6–9.0 eV, while collisional excitation by energetic electron would occur insufficiently to excite these high-energy levels. - Highlights: • This paper describes the excitation mechanism of iron ion in Okamoto-cavity MIP in comparison with conventional ICP. • Boltzmann distribution is studied among iron ionic lines of

  5. Comparative study on contribution of charge-transfer collision to excitations of iron ion between argon radio-frequency inductively-coupled plasma and nitrogen microwave induced plasma

    International Nuclear Information System (INIS)

    This paper describes an ionization/excitation phenomenon of singly-ionized iron occurring in an Okamoto-cavity microwave induced plasma (MIP) as well as an argon radio-frequency inductively-coupled plasma (ICP), by comparing the Boltzmann distribution among iron ionic lines (Fe II) having a wide range of the excitation energy from 4.76 to 9.01 eV. It indicated in both the plasmas that plots of Fe II lines having lower excitation energies (4.76 to 5.88 eV) were fitted on each linear relationship, implying that their excitations were caused by a dominant thermal process such as collision with energetic electron. However, Fe II lines having higher excitation energies (more than 7.55 eV) had a different behavior from each other. In the ICP, Boltzmann plots of Fe II lines assigned to the higher excited levels also followed the normal Boltzmann relationship among the low-lying excited levels, even including a deviation from it in particular excited levels having an excitation energy of ca. 7.8 eV. This deviation can be attributed to a charge-transfer collision with argon ion, which results in the overpopulation of these excited levels, but the contribution is small. On the other hand, the distribution of the high-lying excited levels was non-thermal in the Okamoto-cavity MIP, which did not follow the normal Boltzmann relationship among the low-lying excited levels. A probable reason for the non-thermal characteristics in the MIP is that a charge-transfer collision with nitrogen molecule ion having many vibrational/rotational levels could work for populating the 3d64p (3d54s4p) excited levels of iron ion broadly over an energy range of 7.6–9.0 eV, while collisional excitation by energetic electron would occur insufficiently to excite these high-energy levels. - Highlights: • This paper describes the excitation mechanism of iron ion in Okamoto-cavity MIP in comparison with conventional ICP. • Boltzmann distribution is studied among iron ionic lines of various

  6. Radio frequency detection assembly and method for detecting radio frequencies

    Science.gov (United States)

    Cown, Steven H.; Derr, Kurt Warren

    2010-03-16

    A radio frequency detection assembly is described and which includes a radio frequency detector which detects a radio frequency emission produced by a radio frequency emitter from a given location which is remote relative to the radio frequency detector; a location assembly electrically coupled with the radio frequency detector and which is operable to estimate the location of the radio frequency emitter from the radio frequency emission which has been received; and a radio frequency transmitter electrically coupled with the radio frequency detector and the location assembly, and which transmits a radio frequency signal which reports the presence of the radio frequency emitter.

  7. Detrapping of tungsten nanoparticles in a direct-current argon glow discharge

    International Nuclear Information System (INIS)

    Nanoparticles are grown from the sputtering of a tungsten cathode in a direct current argon glow discharge. Laser light scattering of a vertical laser sheet going through the plasma reveals that the dust particle cloud is compressed and pushed towards the anode during the discharge. Scanning electron microscopy images of substrates exposed to the plasma for given durations show that dust particles are continuously falling down on the anode during the discharge. These observations are explained by the fact that the electrostatic force at the negative glow-anode sheath boundary cannot balance the ion drag, gravity, and thermophoresis forces for particles of more than a few tens of nanometres in diameter

  8. Irradiation of silver and agar/silver nanoparticles with argon, oxygen glow discharge plasma, and mercury lamp

    OpenAIRE

    Ahmad, Mahmoud M; Abdel-Wahab, Essam A; El-Maaref, A A; Rawway, Mohammed; Shaaban, Essam R

    2014-01-01

    The irradiation effect of argon, oxygen glow discharge plasma, and mercury lamp on silver and agar/silver nanoparticle samples is studied. The irradiation time dependence of the synthesized silver and agar/silver nanoparticle absorption spectra and their antibacterial effect are studied and compared. In the agar/silver nanoparticle sample, as the irradiation time of argon glow discharge plasma or mercury lamp increases, the peak intensity and the full width at half maximum, FWHM, of the surfa...

  9. Sputter crater formation in the case of microsecond pulsed glow discharge in a Grimm-type source. Comparison of direct current and radio frequency modes

    International Nuclear Information System (INIS)

    Depth profiling with pulsed glow discharge is a promising technique. The application of pulsed voltage for sputtering reduces the sputtering rate and thermal stress and hereby improves the analysis of thin layered and thermally fragile samples. However pulsed glow discharge is not well studied and this limits its practical use. The current work deals with the questions which usually arise when the pulsed mode is applied: Which duty cycle, frequency and pulse length must be chosen to get the optimal sputtering rate and crater shape? Are the well-known sputtering effects of the continuous mode valid also for the pulsed regime? Is there any difference between dc and rf pulsing in terms of sputtering? It is found that the pulse length is a crucial parameter for the crater shape and thermal effects. Sputtering with pulsed dc and rf modes is found to be similar. The observed sputtering effects at various pulsing parameters helped to interpret and optimize the depth resolution of GD OES depth profiles. - Highlights: ► The validity of the Boumans equation for pulsed rf and dc glow discharge is shown. ► The influence of the pulsing parameters on the sputter crater is ascertained. ► The dependence of the depth resolution on the pulsing parameters is shown. ► Rf and dc pulsed discharges are found to be similar in terms of sputtering.

  10. Generation of uniform atmospheric pressure argon glow plasma by dielectric barrier discharge

    Indian Academy of Sciences (India)

    Raju Bhai Tyata; Deepak Prasad Subedi; Rajendra Shrestha; Chiow San Wong

    2013-03-01

    In this paper, atmospheric pressure glow discharges (APGD) in argon generated in parallel plate dielectric barrier discharge system is investigated by means of electrical and optical measurements. Using a high voltage (0–20 kV) power supply operating at 10–30 kHz, homogeneous and steady APGD has been observed between the electrodes with gap spacing from 0.5 mm to 2 mm and with a dielectric barrier of thickness 2 mm while argon gas is fed at a controlled flow rate of 11/min. The electron temperature and electron density of the plasma are determined by means of optical emission spectroscopy. Our results show that the electron density of the discharge obtained is of the order of 1016 cm-3 while the electron temperature is estimated to be 0.65 eV. The important result is that electron density determined from the line intensity ratio method and stark broadening method are in very good agreement. The Lissajous figure is used to estimate the energy deposited to the glow discharge. It is found that the energy deposited to the discharge is in the range of 20 to 25 $\\$J with a discharge voltage of 1.85 kV. The energy deposited to the discharge is observed to be higher at smaller gas spacing. The glow discharge plasma is tested to be effective in reducing the hydrophobicity of polyethylene film significantly.

  11. Synthesis and characterization of SiC:H ultrafine powder generated in an argon-silane-methane low-pressure radio-frequency discharge

    Science.gov (United States)

    Vivet, F.; Bouchoule, A.; Boufendi, L.

    1998-06-01

    The peculiarity of dusty plasma reactors offers a convenient way to obtain processed particles at submicronic levels, with successive layers of different materials grown by using pulsed gas flows, and different plasma chemistries in succession. This concept is applied to the synthesis of silicon carbide (SiC) particles. In this paper two significant situations are reported showing that particles can be synthesized with different properties by varying the process parameters (gas-flow handling, radio-frequency power level). These properties include broad or narrow size dispersion, almost crystalline or amorphous structure, and widely varying Si/C stoichiometry. Monosized particles with high specific surfaces have been obtained by a two-step growth process by using limited radio-frequency power.

  12. Morphological and surface compositional changes in poly(lactide-co-glycolide) tissue engineering scaffolds upon radio frequency glow discharge plasma treatment

    International Nuclear Information System (INIS)

    Chemical functionalisation of polymeric scaffolds with functional groups such as amine could provide optimal conditions for loading of signalling biomolecules over the entire volume of the porous scaffolds. Three-dimensional (both surface and bulk) functionlisation of large volume scaffolds is highly desirable, but preferably without any change to the basic morphological, structural and bulk chemical properties of the scaffolds. In this work, we have carried out and compared treatments of poly(lactide-co-glycolide) tissue engineering scaffolds by two methods, that is, a wet chemical method using ethylenediamine and a glow discharge plasma method using heptylamine as a precursor. The samples thus prepared were analysed by scanning electron microscopy and X-ray photoelectron spectroscopy. The plasma treatment generated amide and protonated amine (NH+) groups which were present in the bulk and on the surface of the scaffold. Amination also occurred for the wet chemical treatments but the structural and chemical integrity were adversely affected

  13. Measurements and models of transient and stationary regimes of glow discharge in argon

    International Nuclear Information System (INIS)

    The experimental and theoretical analyses of different regimes of argon DC glow discharge are reported. The experiments were carried out on the argon gas tube with a plane- parallel electrode system made from OFHC (oxygen-free high thermal conductivity) copper. Modelling of the static breakdown voltages was performed by simple fluid model. The applicability of fluid models for modelling of I - U (current-voltage) characteristics at different values of pd (pressure times inter-electrode distance) is tested. The formative time delays are determined from experiment and compared to modeled values obtained by [1D] and [2D] fluid models. The memory curve t-bar d (τ) (the dependence of the mean value of breakdown time delay on the relaxation time) is presented and the main processes responsible for the memory effect were determined by applying the analytical and numerical models

  14. Argon gas concentration effects on nanostructured molybdenum nitride layer growth using 100 Hz pulsed dc glow discharge

    Science.gov (United States)

    Ikhlaq, U.; Ahmad, R.; Saleem, S.; Shah, M. S.; Umm-i-Kalsoom; Khan, N.; Khalid, N.

    2012-08-01

    The effect of argon concentration (10%-40%) on the surface properties of molybdenum is studied in nitrogen-argon mixture using 100 Hz pulsed dc glow discharge. The analysis is carried out by using X-ray diffractometer (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and Vickers microhardness tester to investigate surface properties of the nitrided samples. XRD results exhibit the formation of molybdenum nitrides. Crystallite size analysis and SEM morphology confirm the growth of nanostructured molybdenum nitride layers. Moreover, significant increase in surface hardness (by a factor of about two times) is found when the sample is treated for 30% argon in nitrogen-argon mixed plasma.

  15. Irradiation of silver and agar/silver nanoparticles with argon, oxygen glow discharge plasma, and mercury lamp.

    Science.gov (United States)

    Ahmad, Mahmoud M; Abdel-Wahab, Essam A; El-Maaref, A A; Rawway, Mohammed; Shaaban, Essam R

    2014-01-01

    The irradiation effect of argon, oxygen glow discharge plasma, and mercury lamp on silver and agar/silver nanoparticle samples is studied. The irradiation time dependence of the synthesized silver and agar/silver nanoparticle absorption spectra and their antibacterial effect are studied and compared. In the agar/silver nanoparticle sample, as the irradiation time of argon glow discharge plasma or mercury lamp increases, the peak intensity and the full width at half maximum, FWHM, of the surface plasmon resonance absorption band is increased, however a decrease of the peak intensity with oxygen glow plasma has been observed. In the silver nanoparticle sample, as the irradiation time of argon, oxygen glow discharge plasma or mercury lamp increases, the peak intensity of the surface plasmon resonance absorption band is increased, however, there is no significant change in the FWHM of the surface plasmon resonance absorption band. The SEM results for both samples showed nanoparticle formation with mean size about 50 nm and 40 nm respectively. Throughout the irradiation time with the argon, oxygen glow discharge plasma or mercury lamp, the antibacterial activity of several kinds of Gram-positive and Gram-negative bacteria has been examined. PMID:25184109

  16. Time dependent argon glow discharge treatment of Al-alloy samples

    Indian Academy of Sciences (India)

    Sunanda J Karandikar; S V Gogawale; A K Dua; K K Kutty

    2001-05-01

    Aluminium alloy ultra-high vacuum system provides a convenient tool to access the UHV region due to short pump down time, its reduced weight, low cost etc. For UHV systems, aluminium and its alloys are preferred materials to stainless steel. A cylindrical discharge chamger of SS 304 with various ports on it, evacuated by turbomoleculer pumping unit is used in the experimental system. A hollow cathode de glow discharge in argon for different time durations is used to treat chemically cleaned ASA 6063 aluminium alloy samples, keeping all other parameters constant. The scanning electron microscope (SEM) is used to examine processed surfaces and to study topographical features. The energy dispersive microanalysis by X-rays (EDX) is used to determine the elemental composition of the samples. The results indicate the physical sputtering taking place in Ar GDC. The etched area increases with discharge time duration. The EDX spectrum shows the inconsistency in weight percentage of various elements of Al-alloy.

  17. Effects of oxygen addition to argon glow discharges: A hybrid Monte Carlo-fluid modeling investigation

    International Nuclear Information System (INIS)

    A hybrid model is developed for describing the effects of oxygen addition to argon glow discharges. The species taken into account in the model include Ar atoms in the ground state and the metastable level, O2 gas molecules in the ground state and two metastable levels, O atoms in the ground state and one metastable level, O3 molecules, Ar+, O+, O2+ and O- ions, as well as the electrons. The hybrid model consists of a Monte Carlo model for electrons and fluid models for the other plasma species. In total, 87 different reactions between the various plasma species are taken into account. Calculation results include the species densities and the importance of their production and loss processes, as well as the dissociation degree of oxygen. The effect of different O2 additions on these calculation results, as well as on the sputtering rates, is discussed.

  18. RF-ARGON PLASMA INDUCED SURFACE MODIFICATION OF PAPER

    OpenAIRE

    HALIL TURGUT SAHIN

    2008-01-01

    The radio frequency (RF) argon plasma induced surface modification of paper revealed novel surface characteristics and substantially changed surface topography. It was found that RF-argon glow discharge affects surface properties resulting in photo-degradation and chain-scission mechanism on paper network structure. High-power and extended treatment time caused increasing elemental carbon, while decreasing the oxygen concentration on paper surface. However, increased hydroxyls and the creatio...

  19. Study of a contracted glow in low-frequency plasma-jet discharges operating with argon

    International Nuclear Information System (INIS)

    In this work, we present an experimental and theoretical study of a low frequency, atmospheric plasma-jet discharge in argon. The discharge has the characteristics of a contracted glow with a current channel of submillimeter diameter and a relatively high voltage cathode layer. In order to interpret the measurements, we consider the separate modeling of each region of the discharge: main channel and cathode layer, which must then be properly matched together. The main current channel was modeled, extending a previous work, as similar to an arc in which joule heating is balanced by lateral heat conduction, without thermal equilibrium between electrons and heavy species. The cathode layer model, on the other hand, includes the emission of secondary electrons by ion impact and by additional mechanisms, of which we considered emission due to collision of atoms excited at metastable levels, and field-enhanced thermionic emission (Schottky effect). The comparison of model and experiment indicates that the discharge can be effectively sustained in its contracted form by the secondary electrons emitted by collision of excited argon atoms, whereas thermionic emission is by far insufficient to provide the necessary electrons

  20. Study of a contracted glow in low-frequency plasma-jet discharges operating with argon

    Energy Technology Data Exchange (ETDEWEB)

    Minotti, F.; Giuliani, L.; Xaubet, M.; Grondona, D. [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, C1428EHA, Buenos Aires, Argentina and Instituto de Física del Plasma (INFIP), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires - UBA, C1428EHA, Buenos Aires (Argentina)

    2015-11-15

    In this work, we present an experimental and theoretical study of a low frequency, atmospheric plasma-jet discharge in argon. The discharge has the characteristics of a contracted glow with a current channel of submillimeter diameter and a relatively high voltage cathode layer. In order to interpret the measurements, we consider the separate modeling of each region of the discharge: main channel and cathode layer, which must then be properly matched together. The main current channel was modeled, extending a previous work, as similar to an arc in which joule heating is balanced by lateral heat conduction, without thermal equilibrium between electrons and heavy species. The cathode layer model, on the other hand, includes the emission of secondary electrons by ion impact and by additional mechanisms, of which we considered emission due to collision of atoms excited at metastable levels, and field-enhanced thermionic emission (Schottky effect). The comparison of model and experiment indicates that the discharge can be effectively sustained in its contracted form by the secondary electrons emitted by collision of excited argon atoms, whereas thermionic emission is by far insufficient to provide the necessary electrons.

  1. Plasma characteristics of argon glow discharge produced by AC power supply operating at low frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Kongpiboolkid, Watcharapon; Mongkolnavin, Rattachat [Department of Physics, Facuty of Science, Chulalongkorn University, Bangkok (Thailand); Plasma Technology and Nuclear Fusion Research Unit, Chulalongkorn University, Bangkok (Thailand)

    2015-04-24

    Non-thermal properties of Argon glow discharge operating with various operating pressures were measured and presented in this work. The Argon plasma is produced by a parallel conducting electrodes coupling with a high voltage AC power supply. The power supply can generate high AC voltage at various frequencies. The frequencies for the operation are in the range of a few kHz. The system is capable of generating electric field between the two metal electrodes discharge system. The characteristics of plasma produced were measured by optical emission spectroscopy (OES) technique where electron temperature (T{sub e}) and electron number density (n{sub e}) can be determined by line intensity ratio method. The value of electron number density was then determined from the Saha-Eggert equation. Our results show that the electron number density of the discharge obtained is of the order of 10{sup −17} − 10{sup −18} m{sup −3} where the electron temperature is between 1.00−2.00 eV for various operating frequencies used which are in good agreement with similar results published earlier.

  2. Plasma characteristics of argon glow discharge produced by AC power supply operating at low frequencies

    International Nuclear Information System (INIS)

    Non-thermal properties of Argon glow discharge operating with various operating pressures were measured and presented in this work. The Argon plasma is produced by a parallel conducting electrodes coupling with a high voltage AC power supply. The power supply can generate high AC voltage at various frequencies. The frequencies for the operation are in the range of a few kHz. The system is capable of generating electric field between the two metal electrodes discharge system. The characteristics of plasma produced were measured by optical emission spectroscopy (OES) technique where electron temperature (Te) and electron number density (ne) can be determined by line intensity ratio method. The value of electron number density was then determined from the Saha-Eggert equation. Our results show that the electron number density of the discharge obtained is of the order of 10−17 − 10−18 m−3 where the electron temperature is between 1.00−2.00 eV for various operating frequencies used which are in good agreement with similar results published earlier

  3. Characterization of a radio frequency hollow electrode discharge at low gas pressures

    Energy Technology Data Exchange (ETDEWEB)

    Ahadi, Amir Mohammad; Rehders, Stefan; Strunskus, Thomas; Faupel, Franz [Institute for Materials Science – Multicomponent Materials, University of Kiel, 24143 Kiel (Germany); Trottenberg, Thomas; Kersten, Holger [Institute of Experimental and Applied Physics, University of Kiel, 24098 Kiel (Germany)

    2015-08-15

    A radio frequency (RF) hollow discharge configuration is presented, which makes use of a combination of RF plasma generation and the hollow cathode effect. The system was especially designed for the treatment of nanoparticles, plasma polymerization, and nanocomposite fabrication. The process gas streams through the plasma in the inner of the cylindrical electrode system. In the here presented measurements, pure argon and argon with oxygen admixtures are exemplarily used. The discharge is characterized by probe measurements in the effluent, electrical measurements of the discharge parameters, and visual observations of the plasma glow. It is found that the RF fluctuations of the plasma potential are weak. The plasma potential resembles the one of a DC hollow cathode discharge, the RF hollow electrode acts as a cathode due to the self-bias, and a high voltage sheath forms in its inner cylinder.

  4. Characterization of a radio frequency hollow electrode discharge at low gas pressures

    International Nuclear Information System (INIS)

    A radio frequency (RF) hollow discharge configuration is presented, which makes use of a combination of RF plasma generation and the hollow cathode effect. The system was especially designed for the treatment of nanoparticles, plasma polymerization, and nanocomposite fabrication. The process gas streams through the plasma in the inner of the cylindrical electrode system. In the here presented measurements, pure argon and argon with oxygen admixtures are exemplarily used. The discharge is characterized by probe measurements in the effluent, electrical measurements of the discharge parameters, and visual observations of the plasma glow. It is found that the RF fluctuations of the plasma potential are weak. The plasma potential resembles the one of a DC hollow cathode discharge, the RF hollow electrode acts as a cathode due to the self-bias, and a high voltage sheath forms in its inner cylinder

  5. Characterization of a radio frequency hollow electrode discharge at low gas pressures

    Science.gov (United States)

    Ahadi, Amir Mohammad; Trottenberg, Thomas; Rehders, Stefan; Strunskus, Thomas; Kersten, Holger; Faupel, Franz

    2015-08-01

    A radio frequency (RF) hollow discharge configuration is presented, which makes use of a combination of RF plasma generation and the hollow cathode effect. The system was especially designed for the treatment of nanoparticles, plasma polymerization, and nanocomposite fabrication. The process gas streams through the plasma in the inner of the cylindrical electrode system. In the here presented measurements, pure argon and argon with oxygen admixtures are exemplarily used. The discharge is characterized by probe measurements in the effluent, electrical measurements of the discharge parameters, and visual observations of the plasma glow. It is found that the RF fluctuations of the plasma potential are weak. The plasma potential resembles the one of a DC hollow cathode discharge, the RF hollow electrode acts as a cathode due to the self-bias, and a high voltage sheath forms in its inner cylinder.

  6. Radio frequency ion source

    CERN Document Server

    Shen Guan Ren; Gao Fu; LiuNaiYi

    2001-01-01

    The study on Radio Frequency Ion Source is mainly introduced, which is used for CIAE 600kV ns Pulse Neutron Generator; and obtained result is also presented. The RF ion source consists of a diameter phi 25 mm, length 200 mm, coefficient of expansion =3.5 mA, beam current on target >=1.5 mA, beam spot =100 h.

  7. Partial constriction in a glow discharge in argon with nitrogen admixture

    International Nuclear Information System (INIS)

    The constriction of the positive column of a glow discharge in argon with nitrogen admixture (0.02–1%) was studied. The discharge was maintained in a tube of 2.8 cm inner diameter and 75 cm length at intermediate pressures (several tens of Torrs), at which the discharge constriction goes by a jump and the hysteresis effect is well pronounced. It was observed that the constriction begins near one of the electrodes and then the constricted region boundary propagates toward the other electrode. The reverse transition occurs in a similar way. The transition time in Ar : N2 mixtures appears to be essentially longer (up to 1 s) than that in pure argon. By varying the power supply voltage in the course of the transition, the boundary between the diffuse and constricted forms of the discharge could be stopped at some position between the electrodes. Such a partially constricted discharge (PCD) is stable and can exist for a long time. A PCD at various locations of the boundary can be formed, different locations being realized at different discharge voltages but at the same discharge current. This corresponds to a vertical segment in the voltage–current characteristic curve. It was found that this segment lies inside the hysteresis loop and connects two branches of the conventional I–V characteristic measured without affecting the discharge during the diffuse-to-constricted or reverse transitions. Plasma parameters in the diffuse and constricted positive columns are estimated and ionization mechanisms are analyzed. The possible reasons for the low velocity of the constriction front in Ar : N2 mixtures and the mechanisms of the stabilization of the PCD are also discussed. (paper)

  8. RADIO FREQUENCY ATTENUATOR

    Science.gov (United States)

    Giordano, S.

    1963-11-12

    A high peak power level r-f attenuator that is readily and easily insertable along a coaxial cable having an inner conductor and an outer annular conductor without breaking the ends thereof is presented. Spaced first and second flares in the outer conductor face each other with a slidable cylindrical outer conductor portion therebetween. Dielectric means, such as water, contact the cable between the flares to attenuate the radio-frequency energy received thereby. The cylindrical outer conductor portion is slidable to adjust the voltage standing wave ratio to a low level, and one of the flares is slidable to adjust the attenuation level. An integral dielectric container is also provided. (AFC)

  9. ULTRAVIOLET INDUCED MOTION OF A FLUORESCENT DUST CLOUD IN AN ARGON DIRECT CURRENT GLOW DISCHARGE PLASMA

    Energy Technology Data Exchange (ETDEWEB)

    Hvasta, M.G.; and Zwicker, A.

    2008-01-01

    Dusty plasmas consist of electrons, ions, neutrals and nm-μm sized particles commonly referred to as dust. In man-made plasmas this dust may represent impurities in a tokamak or plasma etching processing. In astrophysical plasmas this dust forms structures such as planetary rings and comet tails. To study dusty plasma dynamics an experiment was designed in which a 3:1 silica (<5 μm diameter) and fl uorescent dust mixture was added to an argon DC glow discharge plasma and exposed to UV radiation. This fl uorescent lighting technique offers an advantage over laser scattering (which only allows two-dimensional slices of the cloud to be observed) and is simpler than scanning mirror techniques or particle image velocimetry. Under typical parameters (P=150 mTorr, V anode= 100 V, Vcathode= -400 V, Itotal < 2mA) when the cloud is exposed to the UV light (100W, λ = 365 nm) the mixture fl uoresces, moves ~2mm towards the light source and begins rotating in a clockwise manner (as seen from the cathode). By calibrating a UV lamp and adjusting the relative intensity of the UV with a variable transformer it was found that both translational and rotational velocities are a function of UV intensity. Additionally, it was determined that bulk cloud rotation is not seen when the dust tray is not grounded while bulk translation is. This ongoing experiment represents a novel way to control contamination in man-made plasmas and a path to a better understanding of UV-bathed plasma systems in space..

  10. The influence of resonance radiation transport on the contraction of a glow discharge in argon

    Science.gov (United States)

    Golubovskii, Yu B.; Maiorov, V. A.

    2015-04-01

    The role of resonance radiation transport in the contraction of a positive column in an argon glow discharge is studied numerically. The theory is based on the self-consistent solution of the ambipolar diffusion equation for electrons, the diffusion equation for metastable atoms and the Biberman-Holstein equation for resonance atoms. To calculate the ionization and excitation rates, the Boltzmann equation is solved in a local approximation taking into account elastic, inelastic and electron-electron collisions. A solution method for a boundary problem is developed which allows one to obtain a hysteresis of the parameters during a continuous transition from a diffuse mode to a contracted mode through an unstable branch. At small currents there is a diffuse discharge where the role of radiation transport is inessential because the radial distributions of electrons and excited atoms are close to the fundamental modes of the corresponding equations. Under these conditions, the traditional approximation of ‘effective lifetime’ is accurate enough. For a contracted discharge, this approximation is not applicable because the higher diffusion and radiation modes play a notable role and a more strict description of radiation transport is required. It is shown that, when radiation transport is taken into account, the width of a filament in a contracted discharge significantly exceeds that obtained in the traditional ‘effective lifetime’ approximation. The critical current, when the discharge abruptly turns into a contracted mode, is shifted towards higher current values. The results obtained in this paper can also relate to a discharge in other inert gases.

  11. Radio Frequency Anechoic Chamber Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Supports the design, manufacture, and test of antenna systems. The facility is also used as an electromagnetic compatibility/radio frequency interference...

  12. Foundations for radio frequency engineering

    CERN Document Server

    Geyi, Wen

    2015-01-01

    The book provides a comprehensive coverage of the fundamental topics in microwave engineering, antennas and wave propagation, and electromagnetic compatibility, including electromagnetic boundary value problems, waveguide theory, microwave resonators, antennas and wave propagation, microwave circuits, principles of electromagnetic compatibility designs, information theory and systems. Deals systematically with fundamental problems in radio frequency engineering, this important volume provides an updated treatment of radio frequency theory and techniques. The book can be used as a one-semester course for senior and first-year graduate students or as a reference for radio frequency engineers and applied physicists.

  13. The radio-frequency quadrupole

    OpenAIRE

    Vretenar, Maurizio

    2013-01-01

    Radio-frequency quadrupole (RFQ) linear accelerators appeared on the accelerator scene in the late 1970s and have since revolutionized the domain of low-energy proton and ion acceleration. The RFQ makes the reliable production of unprecedented ion beam intensities possible within a compact radio-frequency (RF) resonator which concentrates the three main functions of the low-energy linac section: focusing, bunching and accelerating. Its sophisticated electrode structure and strict beam dynamic...

  14. Enhancement of intensities in glow discharge mass spectrometry by using mixtures of argon and helium as plasma gases.

    Science.gov (United States)

    Lange, Britta; Matschat, Ralf; Kipphardt, Heinrich

    2007-12-01

    Glow discharge mass spectrometry (GD-MS) is an excellent technique for fast multi-element analysis of pure metals. In addition to metallic impurities, non-metals also can be determined. However, the sensitivity for these elements can be limited due to their high first ionization potentials. Elements with a first ionization potential close to or higher than that of argon, which is commonly used as discharge gas in GD-MS analysis, are ionized with small efficiency only. To improve the sensitivity of GD-MS for such elements, the influence of different glow-discharge parameters on the peak intensity of carbon, chlorine, fluorine, nitrogen, phosphorus, oxygen, and sulfur in pure copper samples was investigated with an Element GD (Thermo Fisher Scientific) GD-MS. Discharge current, discharge gas flow, and discharge gas composition, the last of which turned out to have the greatest effect on the measured intensities, were varied. Argon-helium mixtures were used because of the very high potential of He to ionize other elements, especially in terms of the high energy level of its metastable states. The effect of different Ar-He compositions on the peak intensity of various impurities in pure copper was studied. With Ar-He mixtures, excellent signal enhancements were achieved in comparison with use of pure Ar as discharge gas. In this way, traceable linear calibration curves for phosphorus and sulfur down to the microg kg(-1) range could be established with high sensitivity and very good linearity using pressed powder samples for calibration. This was not possible when pure argon alone was used as discharge gas. PMID:17940753

  15. Blazars at Low Radio Frequencies

    Science.gov (United States)

    Trüstedt, J.; Kadler, M.; Brüggen, M.; Falcke, H.; Heald, G.; McKean, J.; Mueller, C.; Ros, E.; Schulz, R.; Wilms, J.

    We explore the low radio-frequency properties of the MOJAVE 1 blazar sample using the LOFAR Multi-Frequency Snapshot Sky Survey (MSSS). We find the characteristically flat blazar spectrum to extend down to the LOFAR bands, demonstrating that the emission at these low radio frequencies is still dominated by relativistically beamed emission. As most sources remain unresolved at the MSSS angular resolution, we are reimaging these data using LOFAR baselines beyond the standard MSSS uv-range resulting in an angular resolution of ~24 arcsec. We present first LOFAR images of MOJAVE sources from this project.

  16. Radio frequency propagation made easy

    CERN Document Server

    Faruque, Saleh

    2015-01-01

    This book introduces Radio Frequency Propagation to a broad audience.  The author blends theory and practice to bring readers up-to-date in key concepts, underlying principles and practical applications of wireless communications.  The presentation is designed to be easily accessible, minimizing mathematics and maximizing visuals.

  17. Radio Frequency Solid State Amplifiers

    CERN Document Server

    Jacob, J

    2015-01-01

    Solid state amplifiers are being increasingly used instead of electronic vacuum tubes to feed accelerating cavities with radio frequency power in the 100 kW range. Power is obtained from the combination of hundreds of transistor amplifier modules. This paper summarizes a one hour lecture on solid state amplifiers for accelerator applications.

  18. LEP Radio Frequency Copper Cavities

    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.

  19. Radio Frequency Power Load and Associated Method

    Science.gov (United States)

    Srinivasan, V. Karthik (Inventor); Freestone, Todd M. (Inventor); Sims, William Herbert, III (Inventor)

    2014-01-01

    A radio frequency power load and associated method. A radio frequency power load apparatus may include a container with an ionized fluid therein. The apparatus may include one conductor immersed in a fluid and another conductor electrically connected to the container. A radio frequency transmission system may include a radio frequency transmitter, a radio frequency amplifier connected to the transmitter and a radio frequency power load apparatus connected to the amplifier. The apparatus may include a fluid having an ion source therein, one conductor immersed in a fluid, and another conductor electrically connected to the container. A method of dissipating power generated by a radio frequency transmission system may include constructing a waveguide with ionized fluid in a container and connecting the waveguide to an amplifier of the transmission system.

  20. Radio frequency integrated circuit design

    CERN Document Server

    Rogers, John W M

    2010-01-01

    This newly revised and expanded edition of the 2003 Artech House classic, Radio Frequency Integrated Circuit Design, serves as an up-to-date, practical reference for complete RFIC know-how. The second edition includes numerous updates, including greater coverage of CMOS PA design, RFIC design with on-chip components, and more worked examples with simulation results. By emphasizing working designs, this book practically transports you into the authors' own RFIC lab so you can fully understand the function of each design detailed in this book. Among the RFIC designs examined are RF integrated LC

  1. Radio-frequency power generation

    OpenAIRE

    Carter, Richard G.

    2013-01-01

    This paper reviews the main types of radio-frequency power amplifiers which are, or may be, used for high-power hadron accelerators. It covers tetrodes, inductive output tubes, klystrons and magnetrons with power outputs greater than 10 kW continuous wave or 100 kW pulsed at frequencies from 50 MHz to 30 GHz. Factors affecting the satisfactory operation of amplifiers include cooling, matching and protection circuits are discussed. The paper concludes with a summary of the state of the art for...

  2. Simulation of nanoparticle coagulation in radio-frequency C2H2/Ar microdischarges

    Science.gov (United States)

    Xiang-Mei, Liu; Qi-Nan, Li; Rui, Li

    2016-06-01

    The nanoparticle coagulation is investigated by using a couple of fluid models and aerosol dynamics model in argon with a 5% molecular acetylene admixture rf microdischarges, with the total input gas flow rate of 400 sccm. It co-exists with a homogeneous, secondary electron-dominated low temperature γ-mode glow discharges. The heat transfer equation and flow equation for neutral gas are taken into account. We mainly focused on investigations of the nanoparticle properties in atmospheric pressure microdischarges, and discussed the influences of pressure, electrode spacing, and applied voltage on the plasma density and nanoparticle density profiles. The results show that the characteristics of microdischarges are quite different from those of low pressure radio-frequency discharges. First, the nanoparticle density in the bulk plasma in microdischarges is much larger than that of low pressure discharges. Second, the nanoparticle density of 10 nm experiences an exponential increase as soon as the applied voltage increases, especially in the presheath. Finally, as the electrode spacing increases, the nanoparticle density decreased instead of increasing. Project supported by the Natural Science Foundation of Heilongjiang Province, China (Grant Nos. A2015011 and A2015010), the Postdoctoral Scientific Research Development Fund of Heilongjiang Province, China (Grant No. LBH-Q14159), the Program for Young Teachers Scientific Research in Qiqihar University (Grant No. 2014k-Z11), the National Natural Science Foundation of China (Grant No. 11404180), and the University Nursing Program for Yong Scholars with Creative Talents in Heilongjiang Province, China (Grant No. UNPYSCT-2015095).

  3. Radio frequency system for nuclear fusion

    International Nuclear Information System (INIS)

    The importance of radio frequency waves has been increasing in the area of nuclear fusion since they are indispensable for heating of plasma, etc. This report outlines radio frequency techniques used for nuclear fusion and describes the development of radio frequency systems (radio frequency plasma heating system and current drive system). Presently, in-depth studies are underway at various research institutes to achieve plasma heating by injection of radio frequency electric power. Three ranges of frequencies, ICRF (ion cyclotron range of frequency), LHRF (lower hybrid range of frequency) and ECRF (electron cyclotron range of frequency), are considered promissing for radio frequency heating. Candidate waves for plasma current driving include ECW (electron cyclotron wave), LHW (lower hybrid wave), MSW (magnetic sound wave), ICW (ion cyclotron wave) with minority component, and FW (fast wave). FW is the greatest in terms of current drive efficiency. In general, a radio frequency system for nuclear fusion consists of a radio frequency power source, transmission/matching circuit component and plasma connection component. (Nogami, K.)

  4. Deviation from Boltzmann distribution in excited energy levels of singly-ionized iron in an argon glow discharge plasma for atomic emission spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Lei; Kashiwakura, Shunsuke; Wagatsuma, Kazuaki, E-mail: wagatuma@imr.tohoku.ac.jp

    2012-01-15

    A Boltzmann plot for many iron ionic lines having excitation energies of 4.7-9.1 eV was investigated in an argon glow discharge plasma when the discharge parameters, such as the voltage/current and the gas pressure, were varied. A Grimm-style radiation source was employed in a DC voltage range of 400-800 V at argon pressures of 400-930 Pa. The plot did not follow a linear relationship over a wide range of the excitation energy, but it yielded a normal Boltzmann distribution in the range of 4.7-5.8 eV and a large overpopulation in higher-lying excitation levels of iron ion. A probable reason for this phenomenon is that excitations for higher excited energy levels of iron ion would be predominantly caused by non-thermal collisions with argon species, the internal energy of which is received by iron atoms for the ionization. Particular intense ionic lines, which gave a maximum peak of the Boltzmann plot, were observed at an excitation energy of ca. 7.7 eV. They were the Fe II 257.297-nm and the Fe II 258.111-nm lines, derived from the 3d{sup 5}4s4p {sup 6}P excited levels. The 3d{sup 5}4s4p {sup 6}P excited levels can be highly populated through a resonance charge transfer from the ground state of argon ion, because of good matching in the excitation energy as well as the conservation of the total spin before and after the collision. An enhancement factor of the emission intensity for various Fe II lines could be obtained from a deviation from the normal Boltzmann plot, which comprised the emission lines of 4.7-5.8 eV. It would roughly correspond to a contribution of the charge transfer excitation to the excited levels of iron ion, suggesting that the charge-transfer collision could elevate the number density of the corresponding excited levels by a factor of ca.10{sup 4}. The Boltzmann plots give important information on the reason why a variety of iron ionic lines can be emitted from glow discharge plasmas.

  5. Deviation from Boltzmann distribution in excited energy levels of singly-ionized iron in an argon glow discharge plasma for atomic emission spectrometry

    International Nuclear Information System (INIS)

    A Boltzmann plot for many iron ionic lines having excitation energies of 4.7–9.1 eV was investigated in an argon glow discharge plasma when the discharge parameters, such as the voltage/current and the gas pressure, were varied. A Grimm-style radiation source was employed in a DC voltage range of 400–800 V at argon pressures of 400–930 Pa. The plot did not follow a linear relationship over a wide range of the excitation energy, but it yielded a normal Boltzmann distribution in the range of 4.7–5.8 eV and a large overpopulation in higher-lying excitation levels of iron ion. A probable reason for this phenomenon is that excitations for higher excited energy levels of iron ion would be predominantly caused by non-thermal collisions with argon species, the internal energy of which is received by iron atoms for the ionization. Particular intense ionic lines, which gave a maximum peak of the Boltzmann plot, were observed at an excitation energy of ca. 7.7 eV. They were the Fe II 257.297-nm and the Fe II 258.111-nm lines, derived from the 3d54s4p 6P excited levels. The 3d54s4p 6P excited levels can be highly populated through a resonance charge transfer from the ground state of argon ion, because of good matching in the excitation energy as well as the conservation of the total spin before and after the collision. An enhancement factor of the emission intensity for various Fe II lines could be obtained from a deviation from the normal Boltzmann plot, which comprised the emission lines of 4.7–5.8 eV. It would roughly correspond to a contribution of the charge transfer excitation to the excited levels of iron ion, suggesting that the charge-transfer collision could elevate the number density of the corresponding excited levels by a factor of ca.104. The Boltzmann plots give important information on the reason why a variety of iron ionic lines can be emitted from glow discharge plasmas.

  6. In-situ characterisation of the dynamics of a growing dust particle cloud in a direct-current argon glow discharge

    International Nuclear Information System (INIS)

    The growth and the dynamics of a tungsten nanoparticle cloud were investigated in a direct-current low pressure argon glow discharge. Real-time analyses of the dust particle size and number concentration were performed in-situ by light extinction spectrometry, while spatial dynamics of the cloud was investigated with the laser light-sheet scattering method. Additional off-line electron microscopy and Raman spectroscopy measurements were also performed for comparison purpose. This experimental work reveals the existence of an agglomeration phase followed by the appearance of a new dust particle generation. While growing, the dust cloud is pushed towards the anode and the discharge edge. Afterwards, a new dust particle generation can grow in the space freed by the first generation of nanoparticles. The continuous growth, below the light extinction spectrometry scanning positions, explains the apparent dissimilarities observed between the in-line optical and the off-line electron microscopy analyses. (paper)

  7. In-situ characterisation of the dynamics of a growing dust particle cloud in a direct-current argon glow discharge

    Science.gov (United States)

    Barbosa, S.; Couëdel, L.; Arnas, C.; Kishor Kumar, K.; Pardanaud, C.; Onofri, F. R. A.

    2016-02-01

    The growth and the dynamics of a tungsten nanoparticle cloud were investigated in a direct-current low pressure argon glow discharge. Real-time analyses of the dust particle size and number concentration were performed in-situ by light extinction spectrometry, while spatial dynamics of the cloud was investigated with the laser light-sheet scattering method. Additional off-line electron microscopy and Raman spectroscopy measurements were also performed for comparison purpose. This experimental work reveals the existence of an agglomeration phase followed by the appearance of a new dust particle generation. While growing, the dust cloud is pushed towards the anode and the discharge edge. Afterwards, a new dust particle generation can grow in the space freed by the first generation of nanoparticles. The continuous growth, below the light extinction spectrometry scanning positions, explains the apparent dissimilarities observed between the in-line optical and the off-line electron microscopy analyses.

  8. Operating a radio-frequency plasma source on water vapor

    International Nuclear Information System (INIS)

    A magnetically enhanced radio-frequency (rf) plasma source operating on water vapor has an extensive list of potential applications. In this work, the use of a rf plasma source to dissociate water vapor for hydrogen production is investigated. This paper describes a rf plasma source operated on water vapor and characterizes its plasma properties using a Langmuir probe, a residual gas analyzer, and a spectrometer. The plasma source operated first on argon and then on water vapor at operating pressures just over 300 mtorr. Argon and water vapor plasma number densities differ significantly. In the electropositive argon plasma, quasineutrality requires ni≅ne, where ni is the positive ion density. But in the electronegative water plasma, quasineutrality requires ni+=ni-+ne. The positive ion density and electron density of the water vapor plasma are approximately one and two orders of magnitude lower, respectively, than those of argon plasma. These results suggest that attachment and dissociative attachment are present in electronegative water vapor plasma. The electron temperature for this water vapor plasma source is between 1.5 and 4 eV. Without an applied axial magnetic field, hydrogen production increases linearly with rf power. With an axial magnetic field, hydrogen production jumps to a maximum value at 500 W and then saturates with rf power. The presence of the applied axial magnetic field is therefore shown to enhance hydrogen production.

  9. Development of an atmospheric-pressure homogeneous and cold Ar/O2 plasma source operating in glow discharge

    International Nuclear Information System (INIS)

    An atmospheric-pressure Ar/O2 glow discharge is generated in a parallel bare metal plate reactor with a radio-frequency power supply by introducing a dielectric strip in the inlet of the gas flow. The role of the dielectric strip is discussed experimentally. The allowable oxygen-to-argon ratio reaches 1.0 vol % and the generated Ar/O2 plasma discharge is characterized by a low gas temperature and good spatial homogeneity, implying its feasible application as a type of material treatment for a large-area surface, as illustrated experimentally by the ashing of carbon black.

  10. Performances of helium, neon and argon glow discharges for reduction of fuel hydrogen retention in tungsten, stainless steel and graphite

    International Nuclear Information System (INIS)

    It is quite important to investigate the performance of glow discharge conditionings for controls of in-vessel tritium (T) inventory and hydrogen recycling. For this purpose, first, the deuterium (D) retentions in tungsten (W), graphite (C) and stainless steel (SS) were measured. The retention in W was not small as expected, several times larger than that of SS, although the retention in SS was one order smaller than that of C. Such the large retention in W is owing to the growth of rough surface structure produced by plasma irradiations. For reduction of deuterium retention in W, SS and C, second, inert gas (He, Ne, Ar) glow discharges were conducted under the same condition, and these performances were compared. The removal ratio of deuterium retention was highest in He discharge, and lowest in Ar discharge. These values are well explained by the numerical analyses using SRIM code. The removal ratios for SS and C were significantly large, but quite small for W. This reason is again owing to the rough surface structure in W. For W, thirdly, the hydrogen isotope exchange and the wall baking experiments were conducted. It is found that the wall backing with a temperature higher than 700 K can well reduce the retention, and the hydrogen isotope exchange using deuterium glow discharge is also useful to reduce the tritium retention in the wall. The present results significantly contribute to control the fuel hydrogen retention and to reduce the in-vessel tritium inventory in fusion reactors. (author)

  11. Theoretical and experimental investigation of the plasma source with argon rf barrier discharge at atmospheric pressure

    International Nuclear Information System (INIS)

    Glow characteristics of capacitive radio frequency discharge with isolated electrodes in atmospheric pressure argon in low-current and high-current modes are determined experimentally and calculated by the hybrid hydrodynamic model. Comparative analysis of obtained experimental data and simulated spatio-temporal distributions of concentrations of discharge plasma electrons and heavy species, mean energy of electrons in the RF barrier discharge enabled interpretation of the discharge structure peculiarities in low-current α,α-gamma transition and high-current modes.

  12. Radio-frequency integrated-circuit engineering

    CERN Document Server

    Nguyen, Cam

    2015-01-01

    Radio-Frequency Integrated-Circuit Engineering addresses the theory, analysis and design of passive and active RFIC's using Si-based CMOS and Bi-CMOS technologies, and other non-silicon based technologies. The materials covered are self-contained and presented in such detail that allows readers with only undergraduate electrical engineering knowledge in EM, RF, and circuits to understand and design RFICs. Organized into sixteen chapters, blending analog and microwave engineering, Radio-Frequency Integrated-Circuit Engineering emphasizes the microwave engineering approach for RFICs. Provide

  13. Radio Frequency Fragment Separator at NSCL

    Science.gov (United States)

    Bazin, D.; Andreev, V.; Becerril, A.; Doléans, M.; Mantica, P. F.; Ottarson, J.; Schatz, H.; Stoker, J. B.; Vincent, J.

    2009-07-01

    A new device has been designed and built at NSCL which provides additional filtering of radioactive beams produced via projectile fragmentation. The Radio Frequency Fragment Separator (RFFS) uses the time micro structure of the beams accelerated by the cyclotrons to deflect particles according to their time-of-flight, in effect producing a phase filtering. The transverse RF (Radio Frequency) electric field of the RFFS has superior filtering performance compared to other electrostatic devices, such as Wien filters. Such filtering is critical for radioactive beams produced on the neutron-deficient side of the valley of stability, where strong contamination occurs at intermediate energies from 50 to 200 MeV/u.

  14. Radio Frequency Fragment Separator at NSCL

    International Nuclear Information System (INIS)

    A new device has been designed and built at NSCL which provides additional filtering of radioactive beams produced via projectile fragmentation. The Radio Frequency Fragment Separator (RFFS) uses the time micro structure of the beams accelerated by the cyclotrons to deflect particles according to their time-of-flight, in effect producing a phase filtering. The transverse RF (Radio Frequency) electric field of the RFFS has superior filtering performance compared to other electrostatic devices, such as Wien filters. Such filtering is critical for radioactive beams produced on the neutron-deficient side of the valley of stability, where strong contamination occurs at intermediate energies from 50 to 200 MeV/u.

  15. Radio Frequency Identifiers: What are the Possibilities?

    CERN Document Server

    Elmorshidy, Ahmed

    2010-01-01

    This paper defines the components of radio frequency identifiers (RFID). It also explores the different areas and sectors where RFID can be beneficial. The paper discusses the uses and advantages of RFID in deference, consumer packaged goods (CPG), healthcare, logistics, manufacturing, and retail.

  16. Radio frequency source coding made easy

    CERN Document Server

    Faruque, Saleh

    2015-01-01

    This book introduces Radio Frequency Source Coding to a broad audience. The author blends theory and practice to bring readers up-to-date in key concepts, underlying principles and practical applications of wireless communications. The presentation is designed to be easily accessible, minimizing mathematics and maximizing visuals.

  17. Radio frequency channel coding made easy

    CERN Document Server

    Faruque, Saleh

    2016-01-01

    This book introduces Radio Frequency Channel Coding to a broad audience. The author blends theory and practice to bring readers up-to-date in key concepts, underlying principles and practical applications of wireless communications. The presentation is designed to be easily accessible, minimizing mathematics and maximizing visuals.

  18. Radio Frequency communication for modular robots

    OpenAIRE

    Arimany Castells, Guillem

    2011-01-01

    Projecte realitzat mitjançant programa de mobilitat. University of Southern Denmark.Mærsk Mc-Kinney Møller Institute We explore the suitability of Wireless Radio Frequency (RF) inter-module communication for modular robots. Our hypothesis is that, instead of using Infrared (IR) and wired links, RF could be used for module localization and for local and global communication.

  19. Ultra-Wideband Radio Frequency Identification Systems

    CERN Document Server

    Nekoogar, Faranak

    2012-01-01

    Ultra-Wideband Radio Frequency Identification Systems describes the essentials of radio frequency identification systems as well as their target markets. The authors provide a study of commercially available RFID systems and characterizes their performance in terms of read range and reliability in the presence of conductive and dielectric materials. The capabilities and limitations of some commercial RFID systems are reported followed by comprehensive discussions of the advantages and challenges of using ultra-wideband technology for tag/reader communications. The book presents practical aspects of UWB RFID system such as: pulse generation, remote powering, tag and reader antenna design, as well as special applications of  UWB RFIDs in a simple and easy-to-understand language.

  20. Radio-Frequency Electronics, Circuits and Applications

    Science.gov (United States)

    Hagen, Jon B.

    This accessible and comprehensive book provides an introduction to the basic concepts and key circuits of radio frequency systems, covering fundamental principles which apply to all radio devices, from wireless data transceivers on semiconductor chips to high-power broadcast transmitters. Topics covered include filters, amplifiers, oscillators, modulators, low-noise amplifiers, phase-locked loops, and transformers. Applications of radio frequency systems are described in such areas as communications, radio and television broadcasting, radar, and radio astronomy. The book contains many exercises, and assumes only a knowledge of elementary electronics and circuit analysis. It will be an ideal textbook for advanced undergraduate and graduate courses in electrical engineering, as well as an invaluable reference for researchers and professional engineers in this area, or for those moving into the field of wireless communications.

  1. Radio Frequency Identification (RFID) und Dokumentenlogistik

    OpenAIRE

    Bioly, Sascha; Klumpp, Matthias

    2009-01-01

    This paper presents the development and technical concepts of radio frequency identification (RFID) as well as requirements of document logistics. Combining the two topics possibilities of implementing RFID technologies in document logistics (in finance) are discussed. This highlights the future potential of RFID systems in logistics in general as even in 'low-cost' and 'low-attention' areas as document logistics relevant business impacts and cost savings can be stipulated.

  2. Radio Frequency Interference Mitigation at the WSRT

    OpenAIRE

    Fridman, P. A.; Baan, W. A.; Millenaar, R. P.

    2010-01-01

    The sensitivity of radio astronomical stations is often limited by man-made radio frequency interference (RFI) due to a variety of terrestrial activities. An RFI mitigation subsystem (RFIMS) based on real-time digital signalprocessing is proposed here for the Westerbork Synthesis Radio Telescope based on a powerful field programmable gate array processor. In this system the radio astronomy signals polluted by RFI are "cleaned" with the RFIMS before routine back-end correlation processing take...

  3. Study on the effect of hydrogen addition on the variation of plasma parameters of argon-oxygen magnetron glow discharge for synthesis of TiO2 films

    Directory of Open Access Journals (Sweden)

    Partha Saikia

    2016-04-01

    Full Text Available We report the effect of hydrogen addition on plasma parameters of argon-oxygen magnetron glow discharge plasma in the synthesis of H-doped TiO2 films. The parameters of the hydrogen-added Ar/O2 plasma influence the properties and the structural phases of the deposited TiO2 film. Therefore, the variation of plasma parameters such as electron temperature (Te, electron density (ne, ion density (ni, degree of ionization of Ar and degree of dissociation of H2 as a function of hydrogen content in the discharge is studied. Langmuir probe and Optical emission spectroscopy are used to characterize the plasma. On the basis of the different reactions in the gas phase of the magnetron discharge, the variation of plasma parameters and sputtering rate are explained. It is observed that the electron and heavy ion density decline with gradual addition of hydrogen in the discharge. Hydrogen addition significantly changes the degree of ionization of Ar which influences the structural phases of the TiO2 film.

  4. Study on the effect of hydrogen addition on the variation of plasma parameters of argon-oxygen magnetron glow discharge for synthesis of TiO2 films

    Science.gov (United States)

    Saikia, Partha; Saikia, Bipul Kumar; Bhuyan, Heman

    2016-04-01

    We report the effect of hydrogen addition on plasma parameters of argon-oxygen magnetron glow discharge plasma in the synthesis of H-doped TiO2 films. The parameters of the hydrogen-added Ar/O2 plasma influence the properties and the structural phases of the deposited TiO2 film. Therefore, the variation of plasma parameters such as electron temperature (Te), electron density (ne), ion density (ni), degree of ionization of Ar and degree of dissociation of H2 as a function of hydrogen content in the discharge is studied. Langmuir probe and Optical emission spectroscopy are used to characterize the plasma. On the basis of the different reactions in the gas phase of the magnetron discharge, the variation of plasma parameters and sputtering rate are explained. It is observed that the electron and heavy ion density decline with gradual addition of hydrogen in the discharge. Hydrogen addition significantly changes the degree of ionization of Ar which influences the structural phases of the TiO2 film.

  5. Inkjet Printed Radio Frequency Passive Components

    KAUST Repository

    McKerricher, Garret

    2015-12-01

    Inkjet printing is a mature technique for colourful graphic arts. It excels at customized, large area, high resolution, and small volume production. With the developments in conductive, and dielectric inks, there is potential for large area inkjet electronics fabrication. Passive radio frequency devices can benefit greatly from a printing process, since the size of these devices is defined by the frequency of operation. The large size of radio frequency passives means that they either take up expensive space “on chip” or that they are fabricated on a separate lower cost substrate and somehow bonded to the chips. This has hindered cost-sensitive high volume applications such as radio frequency identification tags. Substantial work has been undertaken on inkjet-printed conductors for passive antennas on microwave substrates and even paper, yet there has been little work on the printing of the dielectric materials aimed at radio frequency passives. Both the conductor and dielectric need to be integrated to create a multilayer inkjet printing process that is capable of making quality passives such as capacitors and inductors. Three inkjet printed dielectrics are investigated in this thesis: a ceramic (alumina), a thermal-cured polymer (poly 4 vinyl phenol), and a UV-cured polymer (acrylic based). For the conductor, both a silver nanoparticle ink as well as a custom in-house formulated particle-free silver ink are explored. The focus is on passives, mainly capacitors and inductors. Compared to low frequency electronics, radio frequency components have additional sensitivity regarding skin depth of the conductor and surface roughness, as well as dielectric constant and loss tangent of the dielectric. These concerns are investigated with the aim of making the highest quality components possible and to understand the current limitations of inkjet-fabricated radio frequency devices. An inkjet-printed alumina dielectric that provides quality factors of 200 and high

  6. Radio frequency transistors principles and practical applications

    CERN Document Server

    Dye, Norm

    1993-01-01

    Cellular telephones, satellite communications and radar systems are adding to the increasing demand for radio frequency circuit design principles. At the same time, several generations of digitally-oriented graduates are missing the essential RF skills. This book contains a wealth of valuable design information difficult to find elsewhere.It's a complete 'tool kit' for successful RF circuit design. Written by experienced RF design engineers from Motorola's semiconductors product section.Book covers design examples of circuits (e.g. amplifiers; oscillators; switches; pulsed power; modular syst

  7. Radio frequency system architecture and design

    CERN Document Server

    Rogers, John W M; Marsland, Ian

    2013-01-01

    Communication devices such as smart phones, GPS systems, and Bluetooth, are now part of our daily lives more than ever before. As our communication equipment becomes more sophisticated, so do the radios and other hardware required to enable that technology. Common radio architectures are required to make this technology work seamlessly.This resource describes practical aspects of radio frequency communications systems design, bridging the gap between system-level design considerations and circuit-level design specifications. Industry experts not only provide detailed calculations and theory to

  8. Radio frequency identification applications in hospital environments.

    Science.gov (United States)

    Wicks, Angela M; Visich, John K; Li, Suhong

    2006-01-01

    Radio frequency identification (RFID) technology has recently begun to receive increased interest from practitioners and academicians. This interest is driven by mandates from major retailers such as Wal-Mart, Target and Metro Group, and the United States Department of Defense, in order to increase the efficiency and visibility of material and information flows in the supply chain. However, supply chain managers do not have a monopoly on the deployment of RFID. In this article, the authors discuss the potential benefits, the areas of applications, the implementation challenges, and the corresponding strategies of RFID in hospital environments. PMID:16913301

  9. Radio Frequency Interference Mitigation at the WSRT

    CERN Document Server

    Fridman, P A; Millenaar, R P

    2010-01-01

    The sensitivity of radio astronomical stations is often limited by man-made radio frequency interference (RFI) due to a variety of terrestrial activities. An RFI mitigation subsystem (RFIMS) based on real-time digital signalprocessing is proposed here for the Westerbork Synthesis Radio Telescope based on a powerful field programmable gate array processor. In this system the radio astronomy signals polluted by RFI are "cleaned" with the RFIMS before routine back-end correlation processing takes place. The high temporal and frequency resolution of RFIMS allows the detection and excision of RFI better than do standard radio telescope back-end configurations.

  10. Radio-frequency scanning tunnelling microscopy.

    Science.gov (United States)

    Kemiktarak, U; Ndukum, T; Schwab, K C; Ekinci, K L

    2007-11-01

    The scanning tunnelling microscope (STM) relies on localized electron tunnelling between a sharp probe tip and a conducting sample to attain atomic-scale spatial resolution. In the 25-year period since its invention, the STM has helped uncover a wealth of phenomena in diverse physical systems--ranging from semiconductors to superconductors to atomic and molecular nanosystems. A severe limitation in scanning tunnelling microscopy is the low temporal resolution, originating from the diminished high-frequency response of the tunnel current readout circuitry. Here we overcome this limitation by measuring the reflection from a resonant inductor-capacitor circuit in which the tunnel junction is embedded, and demonstrate electronic bandwidths as high as 10 MHz. This approximately 100-fold bandwidth improvement on the state of the art translates into fast surface topography as well as delicate measurements in mesoscopic electronics and mechanics. Broadband noise measurements across the tunnel junction using this radio-frequency STM have allowed us to perform thermometry at the nanometre scale. Furthermore, we have detected high-frequency mechanical motion with a sensitivity approaching approximately 15 fm Hz(-1/2). This sensitivity is on par with the highest available from nanoscale optical and electrical displacement detection techniques, and the radio-frequency STM is expected to be capable of quantum-limited position measurements. PMID:17972882

  11. Radio Frequency-Tomography of Solar Flares

    Science.gov (United States)

    Aschwanden, M. J.

    2002-05-01

    The Frequency-Agile Solar Radiotelescope (FASR) is designed to produce simultaneous images of solar phenomena at many frequencies. A data cube with a stack of multiple frequency images can be used for tomographic reconstruction of the 3D density and temperature distribution of flares, based on the free-free emission at cm and mm wavelengths. We simulate a set of multi-frequency images for the Bastille-Day flare of 2000-July-14, based on EUV observations from TRACE and soft X-ray observations from Yohkoh. The 3D model consists of some 200 postflare loops with observationally constrained densities and temperatures. The temporal evolution involves flare plasma heating, a phase of conductive cooling, followed by a phase of radiative cooling. The images simulated at different microwave frequencies reveal a sequence of optically-thick free-free emission layers, which can be "pealed off" like onion shells with increasing radio frequency. We envision a tomographic method that yields information on the density and temperature structure of flare systems and their evolution. Comparison with EUV and soft X-ray based 3D models will also allow to quantify wave scattering at radio frequencies and provide information on small-scale inhomogeneities and wave turbulence. Besides the thermal free-free emission, radio images contain also information on coherent emission processes, such as plasma emission from electron beams and loss-cone emission from gyroresonant trapped particles, conveying information on particle acceleration processes.

  12. Diffuse α-mode atmospheric pressure radio-frequency discharge in neon

    International Nuclear Information System (INIS)

    In this work, a radio-frequency (RF) atmospheric pressure glow discharge burning in neon between planar metal electrodes is achieved for the first time. The RF discharge can operate in two stable modes: in a diffuse α-mode with uniformly covered electrode surfaces and in a constricted γ-mode. Similarities are revealed when the discharge is compared against the RF atmospheric pressure glow discharge in helium, namely both discharges show a discontinuity and a hysteresis in the current–voltage characteristic at the mode transition; the spatio-temporal profiles of the light emission in the α-mode from neon, helium and atomic oxygen are also similar. (fast track communication)

  13. Radio-frequency low-coherence interferometry.

    Science.gov (United States)

    Fernández-Pousa, Carlos R; Mora, José; Maestre, Haroldo; Corral, Pablo

    2014-06-15

    A method for retrieving low-coherence interferograms, based on the use of a microwave photonics filter, is proposed and demonstrated. The method is equivalent to the double-interferometer technique, with the scanning interferometer replaced by an analog fiber-optics link and the visibility recorded as the amplitude of its radio-frequency (RF) response. As a low-coherence interferometry system, it shows a decrease of resolution induced by the fiber's third-order dispersion (β3). As a displacement sensor, it provides highly linear and slope-scalable readouts of the interferometer's optical path difference in terms of RF, even in the presence of third-order dispersion. In a proof-of-concept experiment, we demonstrate 20-μm displacement readouts using C-band EDFA sources and standard single-mode fiber. PMID:24978555

  14. SMART TRAVELLING WITH RADIO FREQUENCY IDENTIFICATION

    Directory of Open Access Journals (Sweden)

    Zainab Rasheed Fahad Mirza

    2013-01-01

    Full Text Available Radio Frequency Identification (RFID technology is being widely used now-a-days and is becoming more popular with every passing day. There are varied applications of this technology in various fields such as industry, communication, travel and transportation. Roads, rail ways, air traffic and container vessel shipping all share underlying abstractions of transportation nets with hubs. This study is concerned with applications of RFID technology with Cloud computing, innovation in the field of travelling and its applications for different modes of transportation at Harbors, airports, train stations, road intersections providing security, coordination, to the users. Combined with other technologies, RFID technology is being used for modern airports baggage system, for railroad car identification, in container transportation systems, for fuel supply control of vehicles, in traffic management system and in travelling information system.

  15. Characteristics of Collision, Capacitive Radio Frequency Sheath

    Institute of Scientific and Technical Information of China (English)

    Zhang Yu; DingWanYu; Wang Wenchun; Liu JinYuan; Wang Xiaogang; Liu Yue

    2005-01-01

    A simple collisional radio frequency (rf) sheath fluid model, which is not restricted by the ratio of rf frequency to ion plasma frequency (β=ωrf/ωpi), was established and solved numerically. In the ion balance equation, the effect of the collision on the ion and the ion velocity is assumed to be a direct ratio to ion velocity. The ion energy distributions (IEDs) calculated in the model in comparison with the experimental data [M. A. Sobolewski, J. K. Olthoff, and Y.C. Wang, J. Appl. Phys. 85, 3966 (1999)], proved the validity of the model. And the effect of the collision on the sheath characteristic was obtained and discussed. This paper demonstrates that the collision frequency is another crucial parameter as well as the ratio β to determine the rf sheath characteristics and the shape of IE Ds.

  16. Radio frequency field assisted cold collisions

    Science.gov (United States)

    Ding, Yijue; D'Incao, Jose; Greene, Chris

    2016-05-01

    The radio frequency (RF) field is a promising but less developed tool to control cold collisions. From the few-body perspective, we study cold atom collisions in an external magnetic field and a single-color RF field. We employ the multi-channel quantum defect theory and the hyperspherical toolkit to solve the two-body and three-body Schrödinger equations. Our results show that RF fields can effectively control the two-body scattering length through Feshbach resonances. Such RF induced Feshbach resonances can be applied to quenching experiments or spinor condensates. Analogous to photo association, RF fields can also associate cold atoms into molecules with a reasonable rate. Moreover, we will discuss the feasibility of using RF fields to control three-body recombination, which may improve the experimental timescale by suppressing three-body losses. This work is supported by the US National Science Foundation.

  17. Optical generation of radio-frequency power

    International Nuclear Information System (INIS)

    An optical technique for high-power radio-frequency (RF) signal generation is described. The technique uses a unique photodetector based on a traveling-wave design driven by an appropriately modulated light source. The traveling-wave photodetector (TWPD) exhibits simultaneously a theoretical quantum efficiency approaching 100 % and a very large electrical bandwidth. Additionally, it is capable of dissipating the high-power levels required for the RF generation technique. The modulated light source is formed by either the beating together of two lasers or by the direct modulation of a light source. A system example is given which predicts RF power levels of 100's of mW's at millimeter wave frequencies with a theoretical ''wall-plug'' efficiency approaching 34%

  18. Nb3Sn for Radio Frequency Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Godeke, A.

    2006-12-18

    In this article, the suitability of Nb3Sn to improve theperformance of superconducting Radio-Frequency (RF)cavities is discussed.The use of Nb3Sn in RF cavitiesis recognized as an enabling technology toretain a veryhigh cavity quality factor (Q0) at 4.2 K and tosignificantly improve the cavity accelerating efficiency per unitlength(Eacc). This potential arises through the fundamental properties ofNb3Sn. The properties that are extensively characterized in theliterature are, however, mainly related to improvements in currentcarrying capacity (Jc) in the vortex state. Much less is available forthe Meissner state, which is of key importance to cavities. Relevantdata, available for the Meissner state is summarized, and it is shown howthis already validates the use of Nb3Sn. In addition, missing knowledgeis highlighted and suggestions are given for further Meissner statespecific research.

  19. Development of A Pulse Radio-Frequency Plasma Jet

    Science.gov (United States)

    Wang, Shou-Guo; Zhao, Ling-Li; Yang, Jing-Hua

    2013-09-01

    A small pulse plasma jet was driven by new developed radio-frequency (RF) power supply of 6.78 MHz. In contrast to the conventional RF 13.56 MHz atmospheric pressure plasma jet (APPJ), the power supply was highly simplified by eliminating the matching unit of the RF power supply and using a new circuit, moreover, a pulse controller was added to the circuit to produce the pulse discharge. The plasma jet was operated in a capacitively coupled manner and exhibited low power requirement of 5 W at atmospheric pressure using argon as a carrier gas. The pulse plasma plume temperature remained at less than 45 °C for an extended period of operation without using water to cool the electrodes. Optical emission spectrum measured at a wide range of 200-1000 nm indicated various excited species which were helpful in applying the plasma jet for surface sterilization to human skin or other sensitive materials. Institude of Plasma Physics, Chinese Academy of Science, Hefei, China.

  20. Characterization of helium/argon working gas systems in a radiofrequency glow discharge atomic emission source. Part I: Optical emission, sputtering and electrical characteristics

    Science.gov (United States)

    Christopher, Steven J.; Hartenstein, Matthew L.; Marcus, R. Kenneth; Belkin, Mikhail; Caruso, Joseph A.

    1998-08-01

    Studies are performed to determine the influence of discharge gas composition (helium/argon working gas mixtures) on the analyte emission signal intensities, sputtering rates, and DC-bias characteristics of an analytical radiofrequency glow discharge atomic emission spectroscopy (RF-GD-AES) source. As the partial pressure of He is increased from 0 to 15 torr, increased emission intensity is observed for a range of bulk and trace elements in NIST 1250 SRM (low alloy steel), regardless of the base pressure of Ar in the source (5 and 9 torr). In contrast to increases in analyte emission intensity of up to 300%, counterindicative decreases in the sputtering rates on the order of about 30-50% are observed. The magnitude of these effects depends on both the partial pressure of helium introduced to the source and the total pressure of the He and Ar gases. Use of relative emission yield (REY) to normalize changes in emission intensity to sputtering rates indicates that excitation efficiencies increase under these conditions. Increases in average electron energy and temperature appear to control this response. Decreases in both analyte emission intensities and sputter rates occur with increasing He partial pressure when the total pressure in the cell remains fixed (11 torr in these studies). Emission yields for the fixed pressure, mixed gas plasmas decrease as the partial pressure of He (He/Ar ratio) in the RF-GD source increases. In this case, decreases in electron number densities appear to dictate the lower REYs. Measurement of DC-bias values at the sample surface provide understanding with respect to the observed changes in sputtering rates as well as suggest the origins of changes in plasma electron energetics. Use of a diamond stylus profilometer provides both the quantitative sputter rate information as well as qualitative insights into the use of mixed gas plasmas for enhanced depth profiling capabilities. The analyte emission characteristics of these mixed gas

  1. Experimental radio frequency link for Ka-band communications applications

    Science.gov (United States)

    Fujikawa, Gene; Conray, Martin J.; Saunders, Alan L.; Pope, Dale E.

    1988-01-01

    An experimental radio frequency link has been demonstrated to provide two-way communication between a remote user ground terminal and a ground-based Ka-band transponder. Bit-error-rate performance and radio frequency characteristics of the communication link were investigated.

  2. Radio frequency discharge with dust particles

    NARCIS (Netherlands)

    Chutov, Y. I.; W. J. Goedheer,; Kravchenko, O. Y.; Zuz, V. M.; Yan, M.; Martins, R.; Ferreira, I.; Fortunato, E.; Kroesen, G.

    2000-01-01

    A 1D PIC/MCC method has been developed for computer simulations of low-pressure RF discharges with dust particles using the method for dust-free discharges. A RF discharge in argon with dust particles distributed uniformly in the interelectrode gap is simulated at parameters providing a possibility

  3. A radio frequency interferometer (RIF) system

    International Nuclear Information System (INIS)

    The authors describe a radio frequency interferometer (RFI) system developed and tested by Lawrence Livermore National Laboratory over the last several years. The basic theory of operation, sample data, and analyzed results are presented and compared to results obtained by conventional TDR means (CORRTEX). A typical shock location measurement used for hydro-yield determination or for energy flow diagnostics comprises a coaxial sensing cable extending from the detonation region to a CORRTEX recording instrument. The single digitizer-based RFI system uses an identical sensing cable installation technique. Recording equipment consists of a CAMAC digitizer module, which produces a sinusoidal probing signal (the signal sent downhole) for each sensing channel (cable), while also coherently sampling the phase of the reflected signal. Each channel is recorded using a single digitizer, providing maximal temporal and spatial resolution, but independent of channel gain or quadruture errors inherent to dual digitizer systems. Interpolation software with suitable look-ahead logic permits determination of complete quadruture information using a single digitizer. This RFI system provides several times better spatial resolution and two orders of magnitude better temporal sampling density than does CORRTEX. It also is less susceptible to electromagnetic pulse distortion and provides a direct means for identifying (and rejecting) any data so contaminated

  4. Detection of radio frequency interference over ocean

    Science.gov (United States)

    Tian, Xiaoxu

    The geostationary satellite television (TV) signals that are reflected off the ocean surfaces could enter the AMSR-E antenna, resulting in RFI (Radio Frequency Interference) contamination in AMSR-E 10.65 and 18.7 GHz channels. If not detected, the presence of RFI signals can result in false retrievals of oceanic environmental parameters (e.g., sea surface temperature, sea surface wind speed, rain water path) from microwave imaging radiance measurements. This study first examined the geometric relationship between the RFI source, geostationary TV satellite, and AMSR-E observation. Then a normalized Principal Component Analysis (NPCA) method is proposed and applied for RFI detection over oceans in Advanced Microwave Scanning Radiometer (AMSR)-E observations. It is found that the RFI-contaminated observations on AMSR-E descending node at 10.65 and 18.7 GHz can be successively detected near coastal areas surrounding Europe and United States continents. The results yielded from the geometric examination at another angle verify those signals detected with NPCA. The proposed NPCA algorithm is applicable in an operational environment for fast data processing and data dissemination, and is different from earlier methods, which often require a priori information.

  5. Development of Radio Frequency Antenna Radiation Simulation Software

    International Nuclear Information System (INIS)

    Antennas are widely used national wide for radio frequency propagation especially for communication system. Radio frequency is electromagnetic spectrum from 10 kHz to 300 GHz and non-ionizing. These radiation exposures to human being have radiation hazard risk. This software was under development using LabVIEW for radio frequency exposure calculation. For the first phase of this development, software purposely to calculate possible maximum exposure for quick base station assessment, using prediction methods. This software also can be used for educational purpose. Some results of this software are comparing with commercial IXUS and free ware NEC software. (author)

  6. Wideband micromachined microphones with radio frequency detection

    Science.gov (United States)

    Hansen, Sean Thomas

    There are many commercial, scientific, and military applications for miniature wideband acoustic sensors, including monitoring the condition or wear of equipment, collecting scientific data, and identifying and localizing military targets. The application of semiconductor micromachining techniques to sensor fabrication has the potential to transform acoustic sensing with small, reproducible, and inexpensive silicon-based microphones. However, such sensors usually suffer from limited bandwidth and from non-uniformities in their frequency response due to squeeze-film damping effects and narrow air gaps. Furthermore, they may be too fragile to be left unattended in a humid or dusty outdoor environment. Silicon microphones that incorporate capacitive micromachined ultrasonic transducer membranes overcome some of the drawbacks of conventional microphones. These micromachined membranes are small and robust enough to be vacuum-sealed, and can withstand atmospheric pressure and submersion in water. In addition, the membrane mechanical response is flat from dc up to ultrasonic frequencies, resulting in a wideband sensor for accurate spectral analysis of acoustic signals. However, a sensitive detection scheme is necessary to detect the small changes in membrane displacement that result from using smaller, stiffer membranes than do conventional microphones. We propose a radio frequency detection technique, in which the capacitive membranes are incorporated into a transmission line. Variations in membrane capacitance due to impinging sound pressure are sensed through the phase variations of a carrier signal that propagates along the line. This dissertation examines the design, fabrication, modeling, and experimental measurements of wideband micromachined microphones using sealed ultrasonic membranes and RF detection. Measurements of fabricated microphones demonstrate less than 0.5 dB variation in their output responses between 0.1 Hz to 100 kHz under electrostatic actuation of

  7. Radio Frequency Micro Ion Thruster for Precision Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Busek proposes to develop radio frequency discharge, gridded micro-ion thruster that produces sub-mN thrust precisely adjustable over a wide dynamic thrust range....

  8. Radio Frequency Micro Ion Thruster for Precision Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Busek proposes to continue development of an engineering model radio frequency discharge, gridded micro ion thruster that produces sub-mN to mN thrust precisely...

  9. Radio Frequency Interference Suppression for Landmine Detection by Quadrupole Resonance

    OpenAIRE

    Liu Guoqing; Jiang Yi; Xiong Hong; Li Jian; Barrall Geoffrey A

    2006-01-01

    The quadrupole resonance (QR) technology can be used as a confirming sensor for buried plastic landmine detection by detecting the explosives within the mine. We focus herein on the detection of TNT mines via the QR sensor. Since the frequency of the QR signal is located within the AM radio frequency band, the QR signal can be corrupted by strong radio frequency interferences (RFIs). Hence to detect the very weak QR signal, RFI mitigation is essential. Reference antennas, which receive RFIs ...

  10. Polarimetric Observations at Low Radio Frequencies

    Science.gov (United States)

    Farnes, J. S.

    2012-06-01

    Magnetic fields play a fundamental role in the evolution of astrophysical systems. These fields can be studied through wide-field spectropolarimetry, which allows for faint polarised signals to be detected at relatively low radio frequencies. An interferometric polarisation mode has recently become available at the Giant Metrewave Radio Telescope (GMRT). A detailed analysis of the GMRT's instrumental response is presented. The findings are used to create a polarisation pipeline, which in combination with rotation measure (RM) Synthesis is used for the detection of extended linearly polarised emission at 610 MHz. A number of compact sources are detected and their Faraday depth and polarisation fraction are reported. New holography observations of the GMRT's primary beam are presented. Instantaneous off-axis polarisation is substantial and scales with the Stokes I beam. The developed beam models are used to reduce direction-dependent instrumental polarisation, and the Stokes I beam is shown to deviate from circular symmetry. A new technique for electric vector polarisation angle calibration is developed that removes the need for known sources on the sky, eliminates ionospheric effects, and avoids a flaw in current methods which could erroneously yield multiple Faraday components for sources that are well-parameterised by a single RM. A sample of nine galaxies from two Southern Compact Groups are then presented, with constraints being placed on the polarised fraction, RM, spectral index, star formation rate, companion sources, and hydrodynamical state. One galaxy has a displaced peak of radio emission that is extended beyond the disk in comparison to the near-IR disk - suggesting the radio disturbance may be a consequence of ram pressure stripping. Linear polarisation is detected from the core of NGC 7552 at 610 MHz, while another three galaxies ESO 0353-G036, NGC 7590, and NGC 7599 are found to be unpolarised. An analysis of additional extended sources allows for an

  11. Interaction between pulsed discharge and radio frequency discharge burst at atmospheric pressure

    Science.gov (United States)

    Zhang, Jie; Guo, Ying; Shi, Yuncheng; Zhang, Jing; Shi, J. J.

    2015-08-01

    The atmospheric pressure glow discharges (APGD) with dual excitations in terms of pulsed voltage and pulse-modulation radio frequency (rf) power are studied experimentally between two parallel plates electrodes. Pulse-modulation applied in rf APGD temporally separates the discharge into repetitive discharge bursts, between which the high voltage pulses are introduced to ignite sub-microsecond pulsed discharge. The discharge characteristics and spatio-temporal evolution are investigated by means of current voltage characteristics and time resolved imaging, which suggests that the introduced pulsed discharge assists the ignition of rf discharge burst and reduces the maintain voltage of rf discharge burst. Furtherly, the time instant of pulsed discharge between rf discharge bursts is manipulated to study the ignition dynamics of rf discharge burst.

  12. Observation of the Emission Spectra of an Atmospheric Pressure Radio-frequency Plasma Jet

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    An atmospheric pressure plasma jet (APPJ) using radio-frequency (13.56 MHz)power has been developed to produce homogeneous glow discharge at low temperature. With optical emission spectroscopy, we observed the excited species (atomic helium, atomic oxygen and metastable oxygen) generated in this APPJ and their dependence on gas composition ratio and RF power. O and O2(b1∑g+) are found in the effluent outside the jet by measuring the emission spectra of effluent perpendicular to the jet. An interesting phenomenon is found that there is an abnormal increase of O emission intensity (777.4 nm) between 10 mm and 40 mm away from the nozzle. This observation result is very helpful in practical operation.

  13. Interaction between pulsed discharge and radio frequency discharge burst at atmospheric pressure

    International Nuclear Information System (INIS)

    The atmospheric pressure glow discharges (APGD) with dual excitations in terms of pulsed voltage and pulse-modulation radio frequency (rf) power are studied experimentally between two parallel plates electrodes. Pulse-modulation applied in rf APGD temporally separates the discharge into repetitive discharge bursts, between which the high voltage pulses are introduced to ignite sub-microsecond pulsed discharge. The discharge characteristics and spatio-temporal evolution are investigated by means of current voltage characteristics and time resolved imaging, which suggests that the introduced pulsed discharge assists the ignition of rf discharge burst and reduces the maintain voltage of rf discharge burst. Furtherly, the time instant of pulsed discharge between rf discharge bursts is manipulated to study the ignition dynamics of rf discharge burst

  14. Interaction between pulsed discharge and radio frequency discharge burst at atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jie [State Key Lab for Modification of Chemical Fibers and Polymer Materials, College of Material Science and Engineering, Donghua University, Shanghai 201620 (China); College of Science, Donghua University, Shanghai 201620 (China); Guo, Ying; Shi, Yuncheng [College of Science, Donghua University, Shanghai 201620 (China); Magnetic Confinement Fusion Research Center, Ministry of Education of the People' s Republic of China, Shanghai 201620 (China); Zhang, Jing; Shi, J. J., E-mail: JShi@dhu.edu.cn [State Key Lab for Modification of Chemical Fibers and Polymer Materials, College of Material Science and Engineering, Donghua University, Shanghai 201620 (China); College of Science, Donghua University, Shanghai 201620 (China); Magnetic Confinement Fusion Research Center, Ministry of Education of the People' s Republic of China, Shanghai 201620 (China)

    2015-08-15

    The atmospheric pressure glow discharges (APGD) with dual excitations in terms of pulsed voltage and pulse-modulation radio frequency (rf) power are studied experimentally between two parallel plates electrodes. Pulse-modulation applied in rf APGD temporally separates the discharge into repetitive discharge bursts, between which the high voltage pulses are introduced to ignite sub-microsecond pulsed discharge. The discharge characteristics and spatio-temporal evolution are investigated by means of current voltage characteristics and time resolved imaging, which suggests that the introduced pulsed discharge assists the ignition of rf discharge burst and reduces the maintain voltage of rf discharge burst. Furtherly, the time instant of pulsed discharge between rf discharge bursts is manipulated to study the ignition dynamics of rf discharge burst.

  15. Protection of Hawaii’s observatories from light pollution and radio frequency interference

    Science.gov (United States)

    Wainscoat, Richard

    2015-08-01

    The island of Hawaii is home to Maunakea Observatory, the largest collection of optical and infrared telescopes in the world. Haleakala Observatory on Maui is also an excellent observing site, and is home to the Pan-STARRS telescopes, the Faulkes Telescope North, solar telescopes, and military telescopes.The dark night sky over Maunakea has been well protected by a strong lighting ordinance, and remains very dark. The National Park Service night sky team recently visited Maunakea, and found it to have a darker night sky than any of the US National Parks that they have visited.Haleakala is more threatened, because Maui has a weaker lighting ordinance, and it is a smaller island, meaning that people live and work closer to the telescopes. Haleakala is also closer to Honolulu, and the urban glow from Honolulu contributes to an artificially bright sky in the northwest direction. Although there is no astronomical research done on the island of Kauai, it has some of the best lighting in the world, because endangered birds on Kauai become confused and disoriented by unshielded lights.The county and state lighting regulations will be described in detail. Enforcement issues will also be discussed.The efforts that have been made to protect Maunakea observatory from radio frequency interference, and to reduce radio frequency interference on Haleakala will also be described.

  16. Electric and spectroscopic properties of argon-hydrogen RF microplasma jets at atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Souza-Correa, J A; Oliveira, C; Amorim, J [Laboratorio Nacional de Ciencia e Tecnologia do Bioetanol-CTBE, Caixa Postal 6170, 13083-970, Campinas, Sao Paulo (Brazil); Gomes, M P, E-mail: jorge.correa@bioetanol.org.b, E-mail: carlos.filho@bioetanol.org.b, E-mail: gomesmp@ita.b, E-mail: jayr.amorim@bioetanol.org.b [Departamento de Fisica, Instituto Tecnologico de Aeronautica-ITA, Praca Marechal Eduardo Gomes 50, 12.228-900, Sao Jose dos Campos, Sao Paulo (Brazil)

    2010-10-06

    Microplasma jets of argon-hydrogen (Ar-H{sub 2}) gas mixture were generated by 144.0 MHz radio-frequency (RF) waves at powers of 5 W, 10 W, 20 W and 50 W. The experimental setup employed creates stable microplasmas at atmospheric pressure from 5.0 mm up to 20.0 mm visual glow lengths. We have determined the rms voltages, the rms electric currents and the power absorptions of these microplasma jets. By making use of optical spectroscopy, the emission spectra of Ar-H{sub 2} microplasma jets were recorded in the range 3060-8200 A, in order to estimate the axial distribution profiles of electron density, rotational temperature, excitation temperature and hydrogen atomic temperature.

  17. K-Band Radio frequency Interference Survey of Southeastern Michigan

    DEFF Research Database (Denmark)

    Curry, Shannon; Ahlers, Michael Faursby; Elliot, Harvey;

    2010-01-01

    The Radio frequency Interference Survey of Earth (RISE) is a new type of instrument used to survey and characterize the presence of Radio Frequency Interference (RFI) that can affect microwave radiometers. It consists of a combined microwave radiometer and kurtosis spectrometer with broad frequency...... coverage and high temporal and spectral resolution. A K-Band airborne version has been built and flown across southeast Michigan. A kurtosis detector is included in RISE to reliably detect the presence of RFI, even at very low levels, and to aid in its characterization. A radiometer is included to measure...... the impact of the RFI on observed brightness temperature....

  18. Energy harvesting from radio frequency propagation using piezoelectric cantilevers

    KAUST Repository

    Al Ahmad, Mahmoud

    2012-02-01

    This work reports an induced strain in a piezoelectric cantilever due to radio frequency signal propagation. The piezoelectric actuator is coupled to radio frequency (RF) line through a gap of 0.25 mm. When a voltage signal of 10 Vpp propagates in the line it sets an alternating current in the actuator electrodes. This flowing current drives the piezoelectric cantilever to mechanical movement, especially when the frequency of the RF signal matches the mechanical resonant frequency of the cantilever. Output voltage signals versus frequency for both mechanical vibrational and RF signal excitations have been measured using different loads.© 2011 Elsevier Ltd. All rights reserved.

  19. Characterization of the plasma in a radio-frequency magnetron sputtering system

    International Nuclear Information System (INIS)

    In order to understand the fundamental mechanisms in a radio-frequency magnetron sputtering system, the main properties of the argon plasma used in the process have been measured. A complete three-dimensional map of the ion density, electron temperature, and plasma potential has been obtained using a Langmuir probe. The electron temperature as well as the ion density have been found to increase in the region of the so called race track at the cathode. Furthermore, from the plasma potential map, the time-averaged local electric field has been obtained, pointing out the race track as the region where the most intense ion bombardment takes place. Besides, only the ions produced near the race track are accelerated towards the cathode, whereas those produced in the remaining volume move towards the anode. Finally, the dependence of the plasma quantities on the incident radio-frequency power and deposition pressure has been studied. The plasma potential measured using the Langmuir probe has been found to agree with that determined using an energy resolved mass spectrometer in all studied conditions

  20. Radio-frequency and microwave energies, magnetic and electric fields

    Science.gov (United States)

    Michaelson, S. M.

    1975-01-01

    The biological effects of radio frequency, including microwave, radiation are considered. Effects on body temperature, the eye, reproductive systems, internal organs, blood cells, the cardiovascular system, and the central nervous system are included. Generalized effects of electric and magnetic fields are also discussed. Experimentation with animals and clinical studies on humans are cited, and possible mechanisms of the effects observed are suggested.

  1. Management of radio frequency radiation exposures in telecom Australia

    International Nuclear Information System (INIS)

    Telecom Australia is the largest non-military user of radio frequency radiation (RFR) in Australia and the management of risks to health from RFR exposure are discussed. The Australian RFR Exposure Standard forms that basis of risk assessment. Risk assessment and control procedures including the health surveillance of workers, other special occupational groups and members of the general public are outlined. (author)

  2. Determining radio frequency heating uniformity in mixed beans for disinfestations

    Science.gov (United States)

    Our laboratory collaborates with USDA-ARS in Parlier, CA in developing thermal treatments based on radio frequency (RF) energy for insect control in legumes to meet postharvest phytosanitary regulations for international market. Our current study focuses on lentils and chickpeas that are two importa...

  3. Localized radio frequency communication using asynchronous transfer mode protocol

    Science.gov (United States)

    Witzke, Edward L.; Robertson, Perry J.; Pierson, Lyndon G.

    2007-08-14

    A localized wireless communication system for communication between a plurality of circuit boards, and between electronic components on the circuit boards. Transceivers are located on each circuit board and electronic component. The transceivers communicate with one another over spread spectrum radio frequencies. An asynchronous transfer mode protocol controls communication flow with asynchronous transfer mode switches located on the circuit boards.

  4. Monitoring of tumor radio frequency ablation using derivative spectroscopy

    NARCIS (Netherlands)

    Spliethoff, J.W.; Tanis, E.; Evers, Daniel James; Hendriks, B.H.; Prevoo, W.; Ruers, T.J.M.

    2014-01-01

    Despite the widespread use of radio frequency (RF) ablation, an effective way to assess thermal tissue damage during and after the procedure is still lacking. We present a method for monitoring RF ablation efficacy based on thermally induced methemoglobin as a marker for full tissue ablation. Diffus

  5. Radio frequency plasma treatments on titanium for enhancement of bioactivity.

    NARCIS (Netherlands)

    Lopez-Heredia, M.A.; Legeay, G.; Gaillard, C.; Layrolle, P.

    2008-01-01

    Titanium and its alloys, when treated in alkali solutions, are able to form calcium phosphate coatings on their surface after immersion in supersaturated solutions. In this study, the surfaces of titanium alloy discs were modified by an alkali treatment and a radio frequency (RF) plasma procedure (1

  6. Radio-frequency energy in fusion power generation

    International Nuclear Information System (INIS)

    The history of radio-frequency (rf) energy in fusion experiments is reviewed, and the status of current efforts is described. Potential applications to tasks other than plasma heating are described, as are the research and development needs of rf energy technology

  7. Functional processing of wideband radio frequency hopping signals

    OpenAIRE

    Bobkov, V. B.; V. V. Danilov; Mikityuk, V. I.; Smirnov, E.N.; Skulskii, A. A.; A. V. Yurchenko

    2007-01-01

    Experimental research results of correlation processing of radio frequency hopping signals (FHSS radio signals) with the help of planar domain-acoustic processor are presented. This processor has linear spectrum of reference frequencies which are used for respective consecutive frequency setting during signal generation.

  8. Highly (001)-textured WS2-x films prepared by reactive radio frequency magnetron sputtering

    International Nuclear Information System (INIS)

    Highly (001)-oriented WS2-x films were grown onto oxidized silicon substrates by reactive magnetron sputtering from a metallic tungsten target in argon-hydrogen sulfide mixtures. The best films with respect to the van-der-Waals orientation, i.e. with the (001) planes parallel to the substrate surface, were grown by excitation of the plasma with radio frequency of 27.12 MHz. These films exhibit the largest grains and the lowest film strain. It is shown that this effect is not due to the lower deposition rate at this high excitation frequency. Instead it was found that the lower DC voltage at the sputtering target is advantageous for the film growth since the bombardment of the growing film by highly energetic particles is avoided by this type of plasma excitation. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. SPACE-TIME RESOLVED DIAGNOSTICS OF RADIO FREQUENCY GLOW DISCHARGE KINETICS

    OpenAIRE

    Gottscho, R.

    1987-01-01

    Three applications of space-time resolved spectroscopy to the study of plasma processes are reviewed briefly. Each application emphasizes a different aspect of plasma chemistry : heterogeneous reactions, homogeneous reactions, and charged-particle transport. Spatially-resolved concentration profiles of reactants near surfaces provides estimates for heterogeneous reaction rates. This is demonstrated using data for CF2 molecules near Si and O atoms near Al, graphite, and kapton. Space-time reso...

  10. Radio Frequency Interference Suppression for Landmine Detection by Quadrupole Resonance

    Directory of Open Access Journals (Sweden)

    Liu Guoqing

    2006-01-01

    Full Text Available The quadrupole resonance (QR technology can be used as a confirming sensor for buried plastic landmine detection by detecting the explosives within the mine. We focus herein on the detection of TNT mines via the QR sensor. Since the frequency of the QR signal is located within the AM radio frequency band, the QR signal can be corrupted by strong radio frequency interferences (RFIs. Hence to detect the very weak QR signal, RFI mitigation is essential. Reference antennas, which receive RFIs only, can be used together with the main antenna, which receives both the QR signal and the RFIs, for RFI mitigation. The RFIs are usually colored both spatially and temporally, and hence exploiting only the spatial diversity of the antenna array may not give the best performance. We exploit herein both the spatial and temporal correlations of the RFIs to improve the TNT detection performance.

  11. Plasma heating by radio frequency in the LISA linear machine

    International Nuclear Information System (INIS)

    The characteristics of an experimental apparatus to produce helium plasma by radio frequency and to study its behavior when confined by a magnetic field with mirrors is shown. The plasma was produced by a microwave source of 2.45 GHz and 800 Watts, operating in steady and pulsed state. The plasma parameters were studied as a function of an external magnetic field, for large and small resonance regions. The axial and radial magnetic fields were mapped for each region in order to verify the spatial distribution, particle orbits, and energy confinement time according to the energy balance equation. As a consequence of the influence of the radio frequency (RF) voltage in the plasma the Bohm theory of plasma prob was modified. The diagnostic was done with plane movable electrostatic probe, Hall probe, magnetic probe, diamagnetic coil and spectrography. (Author)

  12. Vacuum arc localization in CLIC prototype radio frequency accelerating structures

    CERN Document Server

    AUTHOR|(CDS)2091976; Koivunen, Visa

    2016-04-04

    A future linear collider capable of reaching TeV collision energies should support accelerating gradients beyond 100 MV/m. At such high fields, the occurrence of vacuum arcs have to be mitigated through conditioning, during which an accelerating structure’s resilience against breakdowns is slowly increased through repeated radio frequency pulsing. Conditioning is very time and resource consuming, which is why developing more efficient procedures is desirable. At CERN, conditioning related research is conducted at the CLIC high-power X-band test stands. Breakdown localization is an important diagnostic tool of accelerating structure tests. Abnormal position distributions highlight issues in structure design, manufacturing or operation and may consequently help improve these processes. Additionally, positioning can provide insight into the physics of vacuum arcs. In this work, two established positioning methods based on the time-difference-ofarrival of radio frequency waves are extended. The first method i...

  13. INTEGRATING RADIO FREQUENCY IDENTIFICATION TECHNOLOGY IN ACADEMIC MANAGEMENT SYSTEM

    OpenAIRE

    Zainab Rasheed Mirza; M. Nawaz Brohi

    2014-01-01

    The purpose of this study is building a web and windows based intelligent system using web technologies, biometric and Radio Frequency Identification technologies (RFID) to strengthen an Academic Management System (AMS) in a campus for monitoring and improving academic performance of teachers and students. A campus mobile phone application will allow guardians to monitor student’s movement history at campus, e-payments and food choices at canteen, class attendance, exam attendance and a...

  14. Longitudinal capture in the radio-frequency-quadrupole structure

    International Nuclear Information System (INIS)

    The radio-frequency-quadrupole (RFQ) linac structure not only can attain easily transverse focusing in the low-beta region, but also can obtain very high capture efficiency because of its low beta-lambda and low-particle rigidity. An optimization study of the zero space-charge longitudinal capture in an RFQ linac that yields configurations with large capture efficiency is described

  15. Electromagnetic induction imaging with a radio-frequency atomic magnetometer

    OpenAIRE

    Deans, C.; Marmugi, L.; Hussain, S.; Renzoni, F.

    2016-01-01

    We report on a compact, tunable, and scalable to large arrays imaging device, based on a radio-frequency optically pumped atomic magnetometer operating in magnetic induction tomography modality. Imaging of conductive objects is performed at room temperature, in an unshielded environment and without background subtraction. Conductivity maps of target objects exhibit not only excellent performance in terms of shape reconstruction but also demonstrate detection of sub-millimetric cracks and pene...

  16. Radio frequency system of the RIKEN ring cyclotron

    International Nuclear Information System (INIS)

    The radio-frequency system of the RIKEN ring cyclotron (K = 540) is required to work in a frequency range of 20 to 45 MHz and to generate the maximum acceleration voltage 250 kV. A new movable box type variable frequency resonator was designed for that purpose. The final amplifier is capable of supplying RF power of 300 kW. The whole system had been installed at RIKEN in September 1986 and has been working well. (author)

  17. Energy Efficiency Optimization of 5G Radio Frequency Chain Systems

    OpenAIRE

    Zi, Ran; Ge, Xiaohu; Thompson, John; Wang, Cheng-Xiang; Wang, Haichao; Han, Tao

    2016-01-01

    With the massive multi-input multi-output (MIMO) antennas technology adopted for the fifth generation (5G) wireless communication systems, a large number of radio frequency (RF) chains have to be employed for RF circuits. However, a large number of RF chains not only increase the cost of RF circuits but also consume additional energy in 5G wireless communication systems. In this paper we investigate energy and cost efficiency optimization solutions for 5G wireless communication systems with a...

  18. Ultra High-Speed Radio Frequency Switch Based on Photonics

    OpenAIRE

    Jia Ge; Fok, Mable P.

    2015-01-01

    Microwave switches, or Radio Frequency (RF) switches have been intensively used in microwave systems for signal routing. Compared with the fast development of microwave and wireless systems, RF switches have been underdeveloped particularly in terms of switching speed and operating bandwidth. In this paper, we propose a photonics based RF switch that is capable of switching at tens of picoseconds speed, which is hundreds of times faster than any existing RF switch technologies. The high-speed...

  19. Pulsed radio frequency therapy of experimentally induced arthritis in ponies.

    OpenAIRE

    Crawford, W. H.; Houge, J C; Neirby, D T; Di Mino, A; Di Mino, A A

    1991-01-01

    The effect of pulsed radio frequency therapy (PRFT) was evaluated on seven ponies with no arthritis and in 28 ponies in which arthritis was created using intra-articular amphotericin B to induce synovitis in the right middle carpal joint. The ponies were divided into five treatment and two control groups. Two levels of arthritis were created and two dosage levels of PRFT were evaluated. The effect of PRFT on arthritic and nonarthritic joints was measured by comparing synovial fluid parameters...

  20. Design of a 6-bit CMOS digital radio frequency memory

    Science.gov (United States)

    Kranz, Gordon M.; Mehalic, Mark

    The authors describe the implementation of a digital radio frequency memory (DRFM) on a single integrated circuit. A VHSIC Hardware Description Language (VHDL) model of the DRFM was completed and used to design the VLSI components of the DRFM architecture. The model performed the specified time and frequency shift functions. A DRFM, with a 1K memory, a control unit, and a digital single-sideband modulator (DSSM) has been placed onto a silicon single chip layout design.

  1. Effect of Radio Frequency Waves on Plasma Instabilities

    Science.gov (United States)

    Sen, S.

    2015-11-01

    The effect of Radio Frequency waves on low frequency plasma instabilities and turbulence is studied. It is shown that the ponderomotive force can stabilize or destabilize instabilities depending on the power deposition profile and no RF induced flow generation hypothesis is required. Its possible consequence on space and fusion plasma will be discussed. Collaborations with George Vahala from William & Mary, Julio Martinell from UNAM and Atsushi Fukuyama from Kyoto University are acknowledged.

  2. Progress on radio frequency auxiliary heating system designs in ITER

    International Nuclear Information System (INIS)

    ITER will require over 100 MW of auxiliary power for heating, on- and off-axis current drive, accessing the H-mode, and plasma shut-down. The Electron Cyclotron Range of Frequencies (ECRF) and Ion Cyclotron Range of Frequencies (ICRF) are two forms of Radio Frequency (RF) auxiliary power being developed for these applications. Design concepts for both the ECRF and ICRF systems are presented, key features and critical design issues are discussed, and projected performances outlined

  3. Synchrotron Radiation at Radio Frequencies from Cosmic Ray Air Showers

    OpenAIRE

    Suprun, Denis A.; Gorham, Peter W.; Rosner, Jonathan L.

    2002-01-01

    We review some of the properties of extensive cosmic ray air showers and describe a simple model of the radio-frequency radiation generated by shower electrons and positrons as they bend in the Earth's magnetic field. We perform simulations by calculating the trajectory and radiation of a few thousand charged shower particles. The results are then transformed to predict the strength and polarization of the electromagnetic radiation emitted by the whole shower.

  4. Radio frequency spectroscopy of polarons in ultracold Bose gases

    OpenAIRE

    Shashi, Aditya; Grusdt, Fabian; Abanin, Dmitry; Demler, Eugene A.

    2014-01-01

    Recent experimental advances enabled the realization of mobile impurities immersed in a Bose-Einstein condensate (BEC) of ultracold atoms. Here, we consider impurities with two or more internal hyperfine states, and study their radio-frequency (rf) absorption spectra, which correspond to transitions between two different hyperfine states. We calculate rf spectra for the case when one of the hyperfine states involved interacts with the BEC, while the other state is noninteracting, by performin...

  5. Numerical modelling of low temperature radio-frequency hydrogen plasmas

    OpenAIRE

    Zorat, Roberto

    2003-01-01

    In this thesis low temperature hydrogen radio frequency (rf) plasmas discharges are modelled numerically by using both a global model and a Particle- In-Cell (PIC) simulation. Such plasmas are of interest because of their industrial applications and for the development of negative ion sources for fusion plasmas. The global model technique was adapted and then implemented to model rf inductively coupled hydrogen plasma discharges created in the DENISE experiment, with particular attention to t...

  6. Three-dimensional printable radio frequency identification antennas

    OpenAIRE

    Naushahi, Shayan

    2015-01-01

    In this master’s thesis, radio frequency identification (RFID) systems and three-dimensional (3D) printing technology is studied to determine the possibility of printing electrically small 3D antennas for RFID tags. Computer simulations are carried out to design 3D antennas that are printable with 3D printing processes. Three tag antennas with different geometries are proposed, and they are designed to match to the input impedance of an RFID chip at the Ultra High Frequency (UHF) frequencies....

  7. Security assurance in networked radio frequency identification system environment

    OpenAIRE

    Starc, Iztok

    2011-01-01

    Radio frequency identification is an information and communication technology for wireless identification and object labelling. A typical RFID system consists of a tag, a reader and a back-end system connected to a database. Nowadays these systems are present in the private sector industries as well as in the public sector. The RFID system deployment is increasing as high level of automation allows companies the opportunity to re-organize and adapt their business processes to reduce costs, in...

  8. Radio frequency assisted heat pump drying of crushed brick

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, M.G.; Metaxas, A.C. [University of Cambridge (United Kingdom). Electricity Utilisation Group

    1999-04-01

    This paper describes an experimental heat pump batch particulate dryer which has been combined with radio frequency (rf) energy, the latter being operated in a continuous pulsed mode. The results show several improvements resulting from the combination drying process. A simplified mathematical model of the dryer, including the rf heating source, has been developed using mass and energy conservation, which show good agreement with experimental results. (author)

  9. Radio frequency treatments for insect disinfestation of dried legumes

    OpenAIRE

    J. A. Johnson; Wang, S.; Tang, J

    2010-01-01

    Dried legumes (chickpeas, green peas or lentils) are valuable export commodities in the US Pacific Northwest. A major problem in the marketing of these products is infestation by insect pests. Typically, chemical fumigants are used to disinfest product, but regulatory issues, insect resistance, environmental concerns and the increase of the organic market have forced the industry to explore non-chemical alternatives. One possible alternative is the use of radio frequency (RF) energy to rapidl...

  10. Terahertz bandwidth integrated radio frequency spectrum analyzer via nonlinear optics

    CERN Document Server

    Ferrera, Marcello; Pasquazi, Alessia; Peccianti, Marco; Clerici, Matteo; Caspani, Lucia; Chu, Sai T; Little, Brent E; Morandotti, Roberto; Moss, David J

    2014-01-01

    We report an integrated all-optical radio frequency spectrum analyzer based on a ~ 4cm long doped silica glass waveguide, with a bandwidth greater than 2.5 THz. We use this device to characterize the intensity power spectrum of ultrahigh repetition rate mode-locked lasers at repetition rates up to 400 GHz, and observe dynamic noise related behavior not observable with other techniques.

  11. Radio frequency identification (RFID) for Naval Medical Treatment Facilities (MTF)

    OpenAIRE

    Macalanda, Eduardo C.

    2006-01-01

    The application of Radio Frequency Identification (RFID) technology in hospitals is modest primarily due to cost and policy issues. Similar to the evolution of other electronic technologies, unit costs for components have been dramatically reduced in the past few years. Despite the reduction in costs, RFID technology has not yet achieved the tipping point of economic rationality for adoption at most healthcare organizations. Although the technology has been primarily applied to asset manageme...

  12. Radio frequency heating for in-situ remediation of DNAPL

    Energy Technology Data Exchange (ETDEWEB)

    Kasevich, R.S. [KAI Technologies, Woburn, MA (United States)

    1996-08-01

    In-situ radio frequency (RF) heating technology for treating soils contaminated with dense nonaqueous phase liquids (DNAPLs) is described. RF imparts heat to non-conducting materials through the application of carefully controlled RF transmissions, improving contaminant flow characteristics and facilitating separation and removal from subsurface soils. The paper outlines advantages and limitations of RF remediation, process operations, general technology considerations, low permeability media considerations, commercial availability, and costs. Two case histories of RF remediation are briefly summarized. 13 refs., 10 figs.

  13. 78 FR 13893 - Certain Radio Frequency Identification (“RFID”) Products and Components Thereof; Notice of...

    Science.gov (United States)

    2013-03-01

    ... COMMISSION Certain Radio Frequency Identification (``RFID'') Products and Components Thereof; Notice of... Commission has received a complaint entitled Certain Radio Frequency Identification (``RFID'') Products and... frequency identification (``RFID'') products and components thereof. The complaint names as...

  14. The radio-frequency design of an iris-type coupler for the CPHS radio-frequency quadrupole

    Institute of Scientific and Technical Information of China (English)

    XIONG Zheng-Feng; ZHENG Shu-Xin; XING Qing-Zi; GUAN Xia-Ling

    2012-01-01

    The Compact Pulsed Hadron Source (CPHS) project is a university-based proton accelerator platform (13 MeV,16 kW,50 mA peak current,0.5 ms pulse width at 50 Hz) for multi-disciplinary neutron and proton applications.The CPHS linac consists of a 3 MeV radio frequency quadrupole (RFQ) linac and a 13 MeV drift tube linac (DTL).Both the RFQ and DTL share a 325 MHz,2.1 MW klystron source.A single iris-type radio-frequency (RF) coupler is used to feed 537 kW of RF power to the RFQ cavity.Threedimensional electromagnetic models of the ridge-loaded tapered waveguide (RLWG) and the coupler-cavity system are presented,and the design process and results of the RLWG and iris plate are described in detail.

  15. Influence of electrode material on measured ion kinetic-energy distributions in radio-frequency discharges

    International Nuclear Information System (INIS)

    The measurement of ion kinetic energies is important for understanding processes that occur in discharges, e.g., the influence of ions on the etching of semiconductor materials in plasma reactors. Direct measurements of ion kinetic energies striking surfaces exposed to the discharge requires sampling through an orifice in a surface. Difficulties with ion sampling through a small aperture, manifested by errors or distortions in measured ion kinetic-energy distributions (IEDs) have been encountered in previous investigations of both dc and radio-frequency (rf) discharges. The errors are usually most significant at relatively low ion energies. Previous measurements in our laboratory of IEDs for ions sampled through a 0.1-mm hole in a grounded, aluminum electrode for rf discharges in argon showed evidence of reduced detection efficiency (discrimination) for low energy ions (<10 eV), and apparent shifts in the measured ion energies for plasmas generated in other gases. It has been suggested that surface charging at or near the sampling orifice can cause both discrimination and energy shifts. The existence of an insulating, or partially insulating, layer of aluminum oxide on the surface of an electrode allows the possibility of surface-charge accumulation. In the present work, IEDs were measured at both aluminum and 304 stainless-steel grounded electrodes with 0.1 mm sampling orifices in rf plasmas generated in argon and oxygen

  16. Experimental Investigation on Electromagnetic Attenuation by Low Pressure Radio-Frequency Plasma for Cavity Structure

    Science.gov (United States)

    He, Xiang; Zhang, Yachun; Chen, Jianping; Chen, Yudong; Zeng, Xiaojun; Yao, Hong; Tang, Chunmei

    2016-01-01

    This paper reports on an experiment designed to test electromagnetic (EM) attenuation by radio-frequency (RF) plasma for cavity structures. A plasma reactor, in the shape of a hollow cylinder, filled with argon gas at low pressure, driven by a RF power source, was produced by wave-transmitting material. The detailed attenuations of EM waves were investigated under different conditions: the incident frequency is 1-4 GHz, the RF power supply is 13.56 MHz and 1.6-3 kW, and the argon pressure is 75-200 Pa. The experimental results indicate that 5-15 dB return loss can be obtained. From a first estimation, the electron density in the experiment is approximately (1.5-2.2) × 1016 m-3 and the collision frequency is about 11-30 GHz. The return loss of EM waves was calculated using a finite-difference time-domain (FDTD) method and it was found that it has a similar development with measurement. It can be confirmed that RF plasma is useful in the stealth of cavity structures such as jet-engine inlet. supported by National Natural Science Foundation of China (No. 51107033) and the Fundamental Research Funds for the Central Universities of China (No. 2013B33614)

  17. In situ measurement of gas composition changes in radio frequency plasmas using a quartz sensor

    International Nuclear Information System (INIS)

    A simple method using a quartz sensor (Q-sensor) was developed to observe gas composition changes in radio frequency (rf) plasmas. The output depends on the gases' absolute pressure, molecular weight, and viscosity. The pressure-normalized quartz sensor output depends only on the molecular weight and viscosity of the gas. Consequently, gas composition changes can be detected in the plasmas if a sensor can be used in the plasmas. Influences imparted by the plasmas on the sensor, such as those by reactive particles (e.g., radicals and ions), excited species, electrons, temperature, and electric potentials during measurements were investigated to test the applicability of this quartz sensor measurement to plasma. The Q-sensor measurement results for rf plasmas with argon, hydrogen, and their mixtures are reproducible, demonstrating that the Q-sensor measurement is applicable for plasmas. In this work, pressure- and temperature-normalized Q-sensor output (NQO) were used to obtain the gas composition information of plasma. Temperature-normalization of the Q-sensor output enabled quartz sensor measurements near plasma electrodes, where the quartz sensor temperature increases. The changes in NQO agreed with results obtained by gas analysis using a quadrupole mass spectrometer. Results confirmed that the change in NQO is mainly attributable to changes in the densities and kinds of gas molecules in the plasma gas phase, not by other extrinsic influences of plasma. For argon, hydrogen, and argon-hydrogen plasmas, these changes correspond to reduction in nitrogen, production of carbon monoxide, and dissociation of hydrogen molecules, respectively. These changes in NQO qualitatively and somewhat quantitatively agreed with results obtained using gas analysis, indicting that the measurement has a potential application to obtain the gas composition in plasmas without disturbing industrial plasma processes.

  18. Electromagnetic induction imaging with a radio-frequency atomic magnetometer

    Science.gov (United States)

    Deans, Cameron; Marmugi, Luca; Hussain, Sarah; Renzoni, Ferruccio

    2016-03-01

    We report on a compact, tunable, and scalable to large arrays imaging device, based on a radio-frequency optically pumped atomic magnetometer operating in magnetic induction tomography modality. Imaging of conductive objects is performed at room temperature, in an unshielded environment and without background subtraction. Conductivity maps of target objects exhibit not only excellent performance in terms of shape reconstruction but also demonstrate detection of sub-millimetric cracks and penetration of conductive barriers. The results presented here demonstrate the potential of a future generation of imaging instruments, which combine magnetic induction tomography and the unmatched performance of atomic magnetometers.

  19. Eddy current imaging with an atomic radio-frequency magnetometer

    CERN Document Server

    Wickenbrock, Arne; Blanchard, John W; Budker, Dmitry

    2016-01-01

    We use a radio-frequency $^{85}$Rb alkali-vapor cell magnetometer based on a paraffin-coated cell with long spin-coherence time and a small, low-inductance driving coil to create highly resolved conductivity maps of different objects. We resolve sub-mm features in conductive objects, we characterize the frequency response of our technique, and by operating at frequencies up to 250 kHz we are able to discriminate between differently conductive materials based on the induced response. The method is suited to cover a wide range of driving frequencies and can potentially be used for detecting non-metallic objects with low DC conductivity.

  20. INTEGRATING RADIO FREQUENCY IDENTIFICATION TECHNOLOGY IN ACADEMIC MANAGEMENT SYSTEM

    Directory of Open Access Journals (Sweden)

    Zainab Rasheed Mirza

    2014-01-01

    Full Text Available The purpose of this study is building a web and windows based intelligent system using web technologies, biometric and Radio Frequency Identification technologies (RFID to strengthen an Academic Management System (AMS in a campus for monitoring and improving academic performance of teachers and students. A campus mobile phone application will allow guardians to monitor student’s movement history at campus, e-payments and food choices at canteen, class attendance, exam attendance and academic performance on daily basis. Mobile application for students will allow students to view their class schedules, teacher appointments, e-payment statement, warnings or announcements, locate their exam halls and search for classrooms.

  1. A radio frequency helical deflector for keV electrons

    International Nuclear Information System (INIS)

    This paper describes a helical deflector to perform circular sweeps of keV electrons by means of radio frequency fields in a frequency range of 500–1000 MHz. By converting the time dependence of incident electrons to a hit position dependence on a circle, this device can potentially achieve extremely precise timing. The system can be adjusted to the velocity of the electrons to exclude the reduction of deflection sensitivity due to finite transit time effects. The deflection electrodes form a resonant circuit, with quality factor Q in excess of 100, and at resonance the sensitivity of the deflection system is around 1 mm per V of applied RF input

  2. RFID explained a primer on radio frequency identification technologies

    CERN Document Server

    Want, Roy

    2006-01-01

    This lecture provides an introduction to Radio Frequency Identification (RFID), a technology enabling automatic identification of objects at a distance without requiring line-of-sight. Electronic tagging can be divided into technologies that have a power source (active tags), and those that are powered by the tag interrogation signal (passive tags); the focus here is on passive tags. An overview of the principles of the technology divides passive tags into devices that use either near field or far field coupling to communicate with a tag reader. The strengths and weaknesses of the approaches a

  3. Applications of Radio Frequency Identification (RFID) in Mining Industries

    Science.gov (United States)

    Khairul Nizam Mahmad, Mohd; Z, Mohd Remy Rozainy M. A.; Baharun, Norlia

    2016-06-01

    RFID technology has recently become a dream of many companies or organizations because of its strategic potential in transforming mining operations. Now is the perfect time, for RFID technology arise as the next revolution in mining industries. This paper will review regarding the application of RFID in mining industries and access knowledge regarding RFID technology and overseen the opportunity of this technology to become an importance element in mining industries. The application of Radio-Frequency Identification (RFID) in mining industries includes to control of Personal Protective Equipment (PPE), control of personnel to access mining sites and RFID solutions for tracking explosives.

  4. Eddy current imaging with an atomic radio-frequency magnetometer

    Science.gov (United States)

    Wickenbrock, Arne; Leefer, Nathan; Blanchard, John W.; Budker, Dmitry

    2016-05-01

    We use a radio-frequency 85Rb alkali-vapor cell magnetometer based on a paraffin-coated cell with long spin-coherence time and a small, low-inductance driving coil to create highly resolved conductivity maps of different objects. We resolve sub-mm features in conductive objects, we characterize the frequency response of our technique, and by operating at frequencies up to 250 kHz we are able to discriminate between differently conductive materials based on the induced response. The method is suited to cover a wide range of driving frequencies and can potentially be used for detecting non-metallic objects with low DC conductivity.

  5. Novel integrated design framework for radio frequency quadrupoles

    International Nuclear Information System (INIS)

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

  6. Radio frequency system of the RIKEN ring cyclotron

    International Nuclear Information System (INIS)

    The radio-frequency system of the RIKEN ring cyclotron is required to work in a frequency range of 20 to 45 MHz and to generate the maximum acceleration voltage of 250 kV. A new movable box-type variable-frequency resonator which is a compact half wave length coaxial type was developed for the above purpose. Each of two resonators is powered by separate RF power amplifier capable of delivering the power of 300 kW. The whole system was installed in September 1986 and has been working successfully. (author)

  7. Momentum transfer through Landau damping and radio frequency current drive

    International Nuclear Information System (INIS)

    The current drive generated by radio frequency waves is regarded as the momentum transfer from waves to resonant electrons through the Landau damping process. The momentum transfer is evaluated using a well-defined model of Landau damping and the plasma current is formulated from the computation between the acceleration by the effective force acting on electrons and the collision. A deformed distribution function to yield the plasma current is formulated with a Boltzmann equation including a simple collision term. This is the basis of the first order current drive theory at the linear Landau damping. (author)

  8. A radio frequency helical deflector for keV electrons

    Energy Technology Data Exchange (ETDEWEB)

    Gevorgian, L.; Ajvazyan, R.; Kakoyan, V. [A.I. Alikhanyan National Science Laboratory, Yerevan (Armenia); Margaryan, A., E-mail: mat@mail.yerphi.am [A.I. Alikhanyan National Science Laboratory, Yerevan (Armenia); Annand, J.R.M. [Department of Physics & Astronomy, University of Glasgow, G12 8QQ Scotland (United Kingdom)

    2015-06-11

    This paper describes a helical deflector to perform circular sweeps of keV electrons by means of radio frequency fields in a frequency range of 500–1000 MHz. By converting the time dependence of incident electrons to a hit position dependence on a circle, this device can potentially achieve extremely precise timing. The system can be adjusted to the velocity of the electrons to exclude the reduction of deflection sensitivity due to finite transit time effects. The deflection electrodes form a resonant circuit, with quality factor Q in excess of 100, and at resonance the sensitivity of the deflection system is around 1 mm per V of applied RF input.

  9. Terahertz encoding approach for secured chipless radio frequency identification.

    Science.gov (United States)

    Bernier, Maxime; Garet, Frederic; Perret, Etienne; Duvillaret, Lionel; Tedjini, Smail

    2011-08-10

    In this article, we present a new family of chipless tags, which permit encoding of digital data in the terahertz domain. These devices consist of stacked dielectric media whose thicknesses are of the same order as terahertz wavelengths. Since the information is encoded in the volume of these multilayer terahertz tags, they can easily be associated with classical identification techniques (e.g., barcode, radio frequency identification), where information is encoded at the surface of the tag, to provide higher data security. The principle of this encoding approach is studied and experimentally demonstrated in this paper. A 2 bit tag prototype has been realized and measured for validation purposes. PMID:21833143

  10. Radio Frequency Magnetic Field Effects on Electron-Hole Recombination

    International Nuclear Information System (INIS)

    We present measurements of the spectrum (1--80MHz) of the effect of a weak (∼500 μT ) radio frequency magnetic field on the electron-hole recombination of radical ion pairs in solution. Distinct spectra are observed for the pyrene anion/dimethylaniline cation radical pair in which one or both of the radicals are perdeuterated. The radical pair mechanism is developed theoretically and shown to account satisfactorily for both the magnetic field effect and the associated magnetic isotope effect

  11. Radio Frequency Magnetic Field Effects on Electron-Hole Recombination

    Energy Technology Data Exchange (ETDEWEB)

    Woodward, J. R.; Timmel, C. R.; McLauchlan, K. A.; Hore, P. J.

    2001-08-13

    We present measurements of the spectrum (1--80MHz) of the effect of a weak ({approx}500 {mu}T ) radio frequency magnetic field on the electron-hole recombination of radical ion pairs in solution. Distinct spectra are observed for the pyrene anion/dimethylaniline cation radical pair in which one or both of the radicals are perdeuterated. The radical pair mechanism is developed theoretically and shown to account satisfactorily for both the magnetic field effect and the associated magnetic isotope effect.

  12. Development and preliminary results of radio frequency ion source

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Yahong, E-mail: xieyh@ipp.ac.cn; Hu, Chundong; Jiang, Caichao; Chen, Yuqian; Gu, Yumin; Su, Renxue; Xie, Yuanlai; Liu, Zhimin [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

    2016-02-15

    A radio frequency (RF) ion source was designed and developed for neutral beam injector. A RF driver test bed was used with a RF generator with maximum power of 25 kW with 1 MHz frequency and a matching box. In order to study the characteristic of RF plasma generation, the capacitance in the matching box was adjusted with different cases. The results show that lower capacitance will better the stability of the plasma with higher RF power. In the future, new RF coils and matching box will be developed for plasma generators with higher RF power of 50 kW.

  13. A morphological algorithm for improving radio-frequency interference detection

    OpenAIRE

    Offringa, A. R.; van de Gronde, J. J.; Roerdink, J. B. T. M.

    2012-01-01

    A technique is described that is used to improve the detection of radio-frequency interference in astronomical radio observatories. It is applied on a two-dimensional interference mask after regular detection in the time-frequency domain with existing techniques. The scale-invariant rank (SIR) operator is defined, which is a one-dimensional mathematical morphology technique that can be used to find adjacent intervals in the time or frequency domain that are likely to be affected by RFI. The t...

  14. Design of Class-E Radio Frequency Power Amplifier

    OpenAIRE

    Al-Shahrani, Saad Mohammed

    2000-01-01

    Power amplifiers (PA) are typically the most power-consuming building blocks of RF transceivers. Therefore, the design of a high-efficiency radio frequency power amplifier is the most obvious solution to overcoming the battery lifetime limitation in the portable communication systems. A power amplifierà ­s classes (A, AB, B, C, F, E, etc), and design techniques (Load-pull and large-signal S-parameters techniques) are presented. The design accuracy of class-A power amplifier based on the s...

  15. Adaptive Radio Frequency Interference Mitigation for HF Surface Wave Radar

    Institute of Scientific and Technical Information of China (English)

    WAN Xian-rong; KE Heng-yu; CHENG Feng

    2005-01-01

    The paper analyses the characteristics of radio frequency interference (RFI) in HF surface wave radar (HFSWR) which adopts the linear frequency modulated interrupted continuous wave (FMICW). RFI will influence all the range cells including all the positive frequency and negative frequency, and the negative frequency range cells contain only the interference information. Based on the above characteristics, we introduce and analyze a new adaptive interference mitigation beamforming algorithm using the negative frequency range cells samples to estimate the interference covariance matrix. Experimental results confirm that this general and robust algorithm can achieve effective RFI suppression using the data recorded by the HFSWR, located near Zhoushan in Zhejiang China.

  16. Towards the Realization of Graphene Based Flexible Radio Frequency Receiver

    Directory of Open Access Journals (Sweden)

    Maruthi N. Yogeesh

    2015-11-01

    Full Text Available We report on our progress and development of high speed flexible graphene field effect transistors (GFETs with high electron and hole mobilities (~3000 cm2/V·s, and intrinsic transit frequency in the microwave GHz regime. We also describe the design and fabrication of flexible graphene based radio frequency system. This RF communication system consists of graphite patch antenna at 2.4 GHz, graphene based frequency translation block (frequency doubler and AM demodulator and graphene speaker. The communication blocks are utilized to demonstrate graphene based amplitude modulated (AM radio receiver operating at 2.4 GHz.

  17. Dual radio frequency plasma source: Understanding via electrical asymmetry effect

    International Nuclear Information System (INIS)

    On the basis of the global model, the influences of driving voltage and frequency on electron heating in geometrically symmetrical dual capacitively coupled radio frequency plasma have been investigated. Consistent with the experimental and simulation results, non-monotonic behavior of dc self bias and plasma heating with increasing high frequency is observed. In addition to the local maxima of plasma parameters for the integer values of the ratio between the frequencies (ξ), ourstudies also predict local maxima for odd integer values of 2ξ as a consequence of the electrical asymmetry effect produced by dual frequency voltage sources.

  18. Electromagnetic induction imaging with a radio-frequency atomic magnetometer

    CERN Document Server

    Deans, Cameron; Hussain, Sarah; Renzoni, Ferruccio

    2016-01-01

    We report on a compact, tunable, and scalable to large arrays imaging device, based on a radio-frequency optically pumped atomic magnetometer operating in magnetic induction tomography modality. Imaging of conductive objects is performed at room temperature, in an unshielded environment and without background subtraction. Conductivity maps of target objects exhibit not only excellent performance in terms of shape reconstruction but also demonstrate detection of sub-millimetric cracks and penetration of conductive barriers. The results presented here demonstrate the potential of a future generation of imaging instruments, which combine magnetic induction tomography and the unmatched performance of atomic magnetometers.

  19. Potentials for Radio Frequency Identification in AEC/FM

    Institute of Scientific and Technical Information of China (English)

    Karsten Menzel; CONG Zixiang; Luke Allan

    2008-01-01

    Radio frequency identification (RFID) technology has proved to be very effective in industries as di-verse as aircraft manufacturing to health and care. The construction industry has been slow to take up on RFID and this paper will discuss the merits of the technology in its potential for application within the con-struction sector. The paper reports about the prototypical implementation of RFID-based information man-agement in FM-scenarios. The prototypes were tested at University College Cork (UCC). The general appli-cability of RFID for decentralised information management could be demonstrated.

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

    Science.gov (United States)

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

    2016-05-01

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

  1. Radio Frequency-Activated Nanoliposomes for Controlled Combination Drug Delivery.

    Science.gov (United States)

    Malekar, Swapnil A; Sarode, Ashish L; Bach, Alvin C; Bose, Arijit; Bothun, Geoffrey; Worthen, David R

    2015-12-01

    This work was conducted in order to design, characterize, and evaluate stable liposomes containing the hydrophobic drug raloxifene HCl (RAL) and hydrophilic doxycycline HCl (DOX), two potentially synergistic agents for treating osteoporosis and other bone lesions, in conjunction with a radio frequency-induced, hydrophobic magnetic nanoparticle-dependent triggering mechanism for drug release. Both drugs were successfully incorporated into liposomes by lipid film hydration, although combination drug loading compromised liposome stability. Liposome stability was improved by reducing the drug load and by including Pluronics® (PL) in the formulations. DOX did not appear to interact with the phospholipid membranes comprising the liposomes, and its release was maximized in the presence of radio frequency (RF) heating. In contrast, differential scanning calorimetry (DSC) and phosphorus-31 nuclear magnetic resonance ((31)P-NMR) analysis revealed that RAL developed strong interactions with the phospholipid membranes, most notably with lipid phosphate head groups, resulting in significant changes in membrane thermodynamics. Likewise, RAL release from liposomes was minimal, even in the presence of RF heating. These studies may offer useful insights into the design and optimization of multidrug containing liposomes. The effects of RAL on liposome characteristics and drug release performance underscore the importance of appropriate physical-chemical analysis in order to identify and characterize drug-lipid interactions that may profoundly affect liposome properties and performance early in the formulation development process. PMID:25899799

  2. Antarctic Radio Frequency Albedo and Implications for Cosmic Ray Reconstruction

    CERN Document Server

    Besson, D Z; Sullivan, M; Allison, P; Barwick, S W; Baughman, B M; Beatty, J J; Belov, K; Bevan, S; Binns, W R; Chen, C; Chen, P; Clem, J M; Connolly, A; De Marco, D; Dowkontt, P F; DuVernois, M; Goldstein, D; Gorham, P W; Grashorn, E W; Hill, B; Hoover, S; Huang, M; Israel, M H; Javaid, A; Kowalski, J; Learned, J; Liewer, K M; Matsuno, S; Mercurio, B C; Miki, C; Mottram, M; Nam, J; Naudet, C J; Nichol, R J; Palladino, K; Romero-Wolf, A; Ruckman, L; Saltzberg, D; Seckel, D; Shang, R Y; Stockham, M; Varner, G S; Vieregg, A G; Wang, Y

    2013-01-01

    From an elevation of ~38 km, the balloon-borne ANtarctic Impulsive Transient Antenna (ANITA) is designed to detect the up-coming radio frequency (RF) signal resulting from a sub-surface neutrino-nucleon collision. Although no neutrinos have been discovered thus far, ANITA is nevertheless the only experiment to self-trigger on radio frequency emissions from cosmic-ray induced atmospheric air showers. In the majority of those cases, down-coming RF signals are observed via their reflection from the Antarctic ice sheet and back up to the ANITA interferometer. Estimating the energy scale of the incident cosmic rays therefore requires an estimate of the fractional power reflected at the air-ice interface. Similarly, inferring the energy of neutrinos interacting in-ice from observations of the upwards-directed signal refracting out to ANITA also requires consideration of signal coherence across the interface. By comparing the direct Solar RF signal intensity measured with ANITA to the surface-reflected Solar signal ...

  3. Post-correlation radio frequency interference classification methods

    CERN Document Server

    Offringa, A R; Biehl, M; Zaroubi, S; Bernardi, G; Pandey, V N

    2010-01-01

    We describe and compare several post-correlation radio frequency interference classification methods. As data sizes of observations grow with new and improved telescopes, the need for completely automated, robust methods for radio frequency interference mitigation is pressing. We investigated several classification methods and find that, for the data sets we used, the most accurate among them is the SumThreshold method. This is a new method formed from a combination of existing techniques, including a new way of thresholding. This iterative method estimates the astronomical signal by carrying out a surface fit in the time-frequency plane. With a theoretical accuracy of 95% recognition and an approximately 0.1% false probability rate in simple simulated cases, the method is in practice as good as the human eye in finding RFI. In addition it is fast, robust, does not need a data model before it can be executed and works in almost all configurations with its default parameters. The method has been compared using...

  4. Radio frequency plasma processing effects on the emission characteristics of a MeV electron beam cathode

    International Nuclear Information System (INIS)

    Experiments have proven that surface contaminants on the cathode of an electron beam diode influence electron emission current and impedance collapse. This letter reports on an investigation to reduce parasitic cathode current loss and to increase high voltage hold off capabilities by reactive sputter cleaning of contaminants. Experiments have characterized effective radio frequency (rf) plasma processing protocols for high voltage anode endash cathode (A endash K) gaps using a two-stage argon/oxygen and argon rf plasma discharge. Time-resolved optical emission spectroscopy measures contaminant (hydrogen) and bulk cathode (aluminum) plasma emission versus transported axial electron beam current turn on. Experiments were performed at accelerator parameters: V=-0.7 to -1.1 ampersand hthinsp;MV, I(diode)=3 endash 30 ampersand hthinsp;kA, and pulse length=0.4 endash 1.0 ampersand hthinsp;μs. Experiments using a two-stage low power (100 W) argon/oxygen rf discharge followed by a higher power (200 W) pure argon rf discharge yielded an increase in cathode turn-on voltage required for axial current emission from 662±174 ampersand hthinsp;kV to 981±97 ampersand hthinsp;kV. The turn-on time of axial current was increased from 100±22 to 175±42 ampersand hthinsp;ns. copyright 1999 American Institute of Physics

  5. Spread spectrum compressed sensing MRI using chirp radio frequency pulses

    CERN Document Server

    Qu, Xiaobo; Zhuang, Xiaoxing; Yan, Zhiyu; Guo, Di; Chen, Zhong

    2013-01-01

    Compressed sensing has shown great potential in reducing data acquisition time in magnetic resonance imaging (MRI). Recently, a spread spectrum compressed sensing MRI method modulates an image with a quadratic phase. It performs better than the conventional compressed sensing MRI with variable density sampling, since the coherence between the sensing and sparsity bases are reduced. However, spread spectrum in that method is implemented via a shim coil which limits its modulation intensity and is not convenient to operate. In this letter, we propose to apply chirp (linear frequency-swept) radio frequency pulses to easily control the spread spectrum. To accelerate the image reconstruction, an alternating direction algorithm is modified by exploiting the complex orthogonality of the quadratic phase encoding. Reconstruction on the acquired data demonstrates that more image features are preserved using the proposed approach than those of conventional CS-MRI.

  6. Propagation of radio frequency waves through density filaments

    Science.gov (United States)

    Ram, Abhay K.; Hizanidis, Kyriakos

    2015-12-01

    In tokamak fusion plasmas, coherent fluctuations in the form of blobs or filaments are routinely observed in the scrape-off layer. In this paper we develop an analytical formalism for the scattering of radio frequency waves by filaments which are cylindrical with their major axis aligned along the toroidal magnetic field lines. Since the magnitude of the ratio of the density inside the filaments to the background density is generally of order 1, the geometric optics approximation cannot be used to describe the scattering. A full-wave model is formulated which assumes that the plasma is cold and that the plasma in the cylindrical filament has uniform density. The background plasma, in which the filament is present, is also assumed to be cold and uniform. The theoretical framework applies to the scattering of any plasma wave.

  7. Radio frequency plasma nitriding of aluminium at higher power levels

    International Nuclear Information System (INIS)

    Nitriding of aluminium 2011 using a radio frequency plasma at higher power levels (500 and 700 W) and lower substrate temperature (500 deg. C) resulted in higher AlN/Al2O3 ratios than obtained at 100 W and 575 deg. C. AlN/Al2O3 ratios derived from X-ray photoelectron spectroscopic analysis (and corroborated by heavy ion elastic recoil time of flight spectrometry) for treatments preformed at 100 (575 deg. C), 500 (500 deg. C) and 700 W (500 deg. C) were 1.0, 1.5 and 3.3, respectively. Scanning electron microscopy revealed that plasma nitrided surfaces obtained at higher power levels exhibited much finer nodular morphology than obtained at 100 W

  8. High-Performance Control in Radio Frequency Power Amplification Systems

    DEFF Research Database (Denmark)

    Høyerby, Mikkel Christian Kofod

    This thesis presents a broad study of methods for increasing the efficiency of narrow-band radio transmitters. The study is centered around the base station application and TETRA/TEDS networks. The general solution space studied is that of envelope tracking applied to linear class-A/B radio...... frequency power amplifiers (RFPAs) in conjunction with cartesian feedback (CFB) used to linearize the overall transmitter system. On a system level, it is demonstrated how envelope tracking is particularly useful for RF carriers with high peak-to-average power ratios, such as TEDS with 10dB. It is also...... further research. Practically demonstrated is a high-efficiency 25W TEDS transmitter capable of meeting all base station adjacent channel power ratio and wideband noise specifications with ample margins. Efficiency is improved from 23% to 44% by application of envelope tracking - almost a doubling - at...

  9. Radio frequency auxiliary heating systems design in ITER

    International Nuclear Information System (INIS)

    A combination of radio frequency (RF) auxiliary heating systems will provide at least one half of the required 100 MW of auxiliary power in ITER. Five of the 20 equatorial ports are assigned to RF heating systems. Recent work has focused on developing an integrated equatorial port-plug design concept for all of the RF auxiliary heating systems as well as other equatorial port systems such as diagnostics. Common features of the design approach include the use of identical interfaces to services such as cooling water, vacuum, mechanical connection to the vessel, and maintenance. Based on the integrated port concept, a high level of design integration has been achieved for the RF heating systems. Implementation of the integrated design concept has been accomplished without significantly affecting the individual system performance and with limited impact on the torus layout. (author)

  10. Development of radio frequency induction plasma generators for neutral beams

    International Nuclear Information System (INIS)

    The techniques, operational aspects, and experimental results of a radio frequency induction plasma generator, with an internal rf power coupler, intended for intense neutral beam applications are described. One of the development sources suitable for 10 x 10-cm2 extraction optics was operated to a deuterium ion current density of 250 mA/cm2, uniform to 5%, over a circular extraction area 15 cm in diameter with a coupled rf power of 20 kW. Temporal fluctuation levels in the extracted ion current were measured to be typically 1% of the dc level. A second developmental source suitable for 10 x 40-cm2 grid sets was operated to 200 mA/cm2, uniform to +- 8% over a 10 x 40 cm2 area, with 40-kW coupled rf power

  11. Radio-frequency ion deflector for mass separation

    Energy Technology Data Exchange (ETDEWEB)

    Schlösser, Magnus, E-mail: magnus.schloesser@googlemail.com; Rudnev, Vitaly; Ureña, Ángel González, E-mail: laseres@pluri.ucm.es [Unidad de Láseres y Haces Moleculares, Instituto Plurisdisciplinar, Universidad Complutense de Madrid, Madrid 28040 (Spain)

    2015-10-15

    Electrostatic cylindrical deflectors act as energy analyzer for ion beams. In this article, we present that by imposing of a radio-frequency modulation on the deflecting electric field, the ion transmission becomes mass dependent. By the choice of the appropriate frequency, amplitude, and phase, the deflector can be used as mass filter. The basic concept of the new instrument as well as simple mathematic relations are described. These calculations and further numerical simulations show that a mass sensitivity is achievable. Furthermore, we demonstrate the proof-of-principle in experimental measurements, compare the results to those of from a 1 m linear time-of-flight spectrometer, and comment on the mass resolution of the method. Finally, some potential applications are indicated.

  12. Radio-frequency-modulated Rydberg states in a vapor cell

    CERN Document Server

    Miller, Stephanie A; Raithel, Georg

    2016-01-01

    We measure strong radio-frequency (RF) electric fields using rubidium Rydberg atoms prepared in a room-temperature vapor cell as field sensors. Electromagnetically induced transparency is employed as an optical readout. We RF-modulate the 60$S_{1/2}$ and 58$D_{5/2}$ Rydberg states with 50~MHz and 100~MHz fields, respectively. For weak to moderate RF fields, the Rydberg levels become Stark-shifted, and sidebands appear at even multiples of the driving frequency. In high fields, the adjacent hydrogenic manifold begins to intersect the shifted levels, providing rich spectroscopic structure suitable for precision field measurements. A quantitative description of strong-field level modulation and mixing of $S$ and $D$ states with hydrogenic states is provided by Floquet theory. Additionally, we estimate the shielding of DC electric fields in the interior of the glass vapor cell.

  13. Global analysis of radio-frequency current drive

    International Nuclear Information System (INIS)

    A theoretical analysis of radio-frequency current drive in a tokamak at frequencies much less than the electron cyclotron frequency is presented. The global model discussed includes kinetic hot plasma effects and collisions. It is found that all kinds of wave plasma interactions (resonant wave-electron interaction, resonant wave-ion interaction and collisions) can contribute to the current drive. The analysis presented discusses the following important current drive components: the momentum-transfer current and polarization current, the helicity current, the resonant and non resonant currents, the currents caused by kinetic and collisional effects. Expressions for all current drive components are derived, and comparison with the results on helicity current drive obtained by other researchers is given. (author)

  14. Spurs in digital radio frequency memory and applications of DRFM

    Science.gov (United States)

    Nityananda, B. V.

    1993-09-01

    A method to calculate the power level of harmonics generated in digital radio frequency memory (DRFM) due to sampling and quantization process is presented. The Fourier series analysis is used for the calculation of the harmonic levels. The quantization process generates the harmonics of the fundamental signal which is folded into the DRFM instantaneous bandwidth by the sampling process. Power level of the harmonics is dependent on the number of quantization bits of the analog to digital converter. It is also dependent on the ratio of signal frequency to sampling frequency. MATLAB programs for computation of harmonic power levels and plots of harmonic power levels of multibit DRFM are included in the thesis. Some applications of the DRFM, such as deception jammer, broadband frequency source, and radar simulator, are also discussed.

  15. Novel radio-frequency ion trap with spherical geometry

    CERN Document Server

    Noshad, Houshyar

    2014-01-01

    Confinement of single ions in a novel radio-frequency (RF) quadrupole ion trap with spherical shape is investigated. An optimization of this spherical ion trap (SIT) is carried out in order to suppress its nonlinearity substantially by eliminating the electric octupole moment. Hence, a trapping potential and consequently an electric field very similar to the ideal quadrupole ion trap (QIT) are obtained. Afterwards, three stability regions for the optimized SIT are numerically computed. The regions coincide well with those reported in the literature for the ideal QIT. The reason is attributed to the zero electric octupole moment of our proposed trap. The SIT simple geometry and relative ease of fabrication along with its increased trapping volume compared to the conventional hyperbolic quadrupole ion trap, make it an appropriate choice for miniaturization.

  16. A morphological algorithm for improving radio-frequency interference detection

    CERN Document Server

    Offringa, A R; Roerdink, J B T M

    2012-01-01

    A technique is described that is used to improve the detection of radio-frequency interference in astronomical radio observatories. It is applied on a two-dimensional interference mask after regular detection in the time-frequency domain with existing techniques. The scale-invariant rank (SIR) operator is defined, which is a one-dimensional mathematical morphology technique that can be used to find adjacent intervals in the time or frequency domain that are likely to be affected by RFI. The technique might also be applicable in other areas in which morphological scale-invariant behaviour is desired, such as source detection. A new algorithm is described, that is shown to perform quite well, has linear time complexity and is fast enough to be applied in modern high resolution observatories. It is used in the default pipeline of the LOFAR observatory.

  17. Radio frequency interference effect on PN code sequence lock detector

    Science.gov (United States)

    Kwon, Hyuck M.; Tu, Kwei; Loh, Y. C.

    1991-01-01

    The authors find the probabilities of detection and false alarm of the pseudonoise (PN) sequence code lock detector when strong radio frequency interference (RFI) hits the communications link. Both a linear model and a soft-limiter nonlinear model for a transponder receiver are considered. In addition, both continuous wave (CW) RFI and pulse RFI are analyzed, and a discussion is included of how strong CW RFI can knock out the PN code lock detector in a linear or a soft-limiter transponder. As an example, the Space Station Freedom forward S-band PN system is evaluated. It is shown that a soft-limiter transponder can protect the PN code lock detector against a typical pulse RFI, but it can degrade the PN code lock detector performance more than a linear transponder if CW RFI hits the link.

  18. A morphological algorithm for improving radio-frequency interference detection

    Science.gov (United States)

    Offringa, A. R.; van de Gronde, J. J.; Roerdink, J. B. T. M.

    2012-03-01

    A technique is described that is used to improve the detection of radio-frequency interference in astronomical radio observatories. It is applied on a two-dimensional interference mask after regular detection in the time-frequency domain with existing techniques. The scale-invariant rank (SIR) operator is defined, which is a one-dimensional mathematical morphology technique that can be used to find adjacent intervals in the time or frequency domain that are likely to be affected by RFI. The technique might also be applicable in other areas in which morphological scale-invariant behaviour is desired, such as source detection. A new algorithm is described, that is shown to perform quite well, has linear time complexity and is fast enough to be applied in modern high resolution observatories. It is used in the default pipeline of the LOFAR observatory.

  19. Topology optimization of radio frequency and microwave structures

    DEFF Research Database (Denmark)

    Aage, Niels

    This thesis focuses on topology optimization of conductor-based microwave and radio frequency electromagnetic devices. The research is motivated by the ever increasing usage of small hand-held, or autonomous, electric devices, which have lead to a series of new challenges for the design of...... efficient antennas and power supplies. A topology optimization methodology is proposed based on a design parameterization which incorporates the skin effect. The numerical optimization procedure is implemented in Matlab, for 2D problems, and in a parallel C++ optimization framework, for 3D design problems...... lenses are investigated. It is shown that the performance can be increased with more than 30 % compared to a conventional design. The second optimization problem investigated concerns the design of sub-wavelength antennas. In order to alleviate dependence on the initial design and to obtain a generally...

  20. Propagation of radio frequency waves through density filaments

    Energy Technology Data Exchange (ETDEWEB)

    Ram, Abhay K., E-mail: abhay@psfc.mit.edu [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139. USA (United States); Hizanidis, Kyriakos [National Technical University of Athens, Association EURATOM (Greece)

    2015-12-10

    In tokamak fusion plasmas, coherent fluctuations in the form of blobs or filaments are routinely observed in the scrape-off layer. In this paper we develop an analytical formalism for the scattering of radio frequency waves by filaments which are cylindrical with their major axis aligned along the toroidal magnetic field lines. Since the magnitude of the ratio of the density inside the filaments to the background density is generally of order 1, the geometric optics approximation cannot be used to describe the scattering. A full-wave model is formulated which assumes that the plasma is cold and that the plasma in the cylindrical filament has uniform density. The background plasma, in which the filament is present, is also assumed to be cold and uniform. The theoretical framework applies to the scattering of any plasma wave.

  1. Propagation of radio frequency waves through density filaments

    International Nuclear Information System (INIS)

    In tokamak fusion plasmas, coherent fluctuations in the form of blobs or filaments are routinely observed in the scrape-off layer. In this paper we develop an analytical formalism for the scattering of radio frequency waves by filaments which are cylindrical with their major axis aligned along the toroidal magnetic field lines. Since the magnitude of the ratio of the density inside the filaments to the background density is generally of order 1, the geometric optics approximation cannot be used to describe the scattering. A full-wave model is formulated which assumes that the plasma is cold and that the plasma in the cylindrical filament has uniform density. The background plasma, in which the filament is present, is also assumed to be cold and uniform. The theoretical framework applies to the scattering of any plasma wave

  2. Development of a radio frequency excited local impedance probe

    International Nuclear Information System (INIS)

    Local void fraction measurements were made with a Karlsruhe type impedance probe. The probe was operated at radiofrequency to minimize sensitivity to liquid phase resistivity. Two types of signal thresholding were used: level and derivative. A dual beam X-ray system was used as a calibration standard for the radio frequency excited impedance probe. Calibration was performed in vertical air/water flows. Derivative thresholding was found to be preferable to level thresholding, however, in both schemes hydrodynamic and surface tension effects were observed below a liquid superficial velocity of 0.5 m/s. Table salt (NaCl) was added to the water to verify the probe's response to changing water resistivity. Derivative thresholding appeared to work quite well but level thresholding was found to be inadequate due to the change in capacitance. (orig.)

  3. CERN Open Days 2013, Point 4: LHC Radio Frequency

    CERN Multimedia

    CERN Photolab

    2013-01-01

    Stand description: At Point 4 visitors will descend into the LHC tunnel to see the "engine" of the collider: the accelerating cavities where the circulating particles get a small kick of energy as they pass by 11,000 times each second. During your visit underground, you will see the superconducting magnets as well as instruments for observing the beams. You will also walk through the huge cavern containing the Radio Frequency power plants which provide the particle beams with energy. On surface no restricted access  Above ground, you will see the cryogenics installations which keep the accelerator at a just few degrees above absolute zero. Lots of fascinating information and exhibits about CERN's accelerators and experiments will be on display, with CERN engineers and physicists on hand all day to answer your questions.

  4. Radio frequency radiation (RFR) exposures from mobile phones

    International Nuclear Information System (INIS)

    Measurements of the free space levels of radio frequency radiation (RFR) around a hand-held mobile phone and the specific absorption rate (SAR) induced in the ocular region of a phantom head exposed to RFR from a mobile phone are presented. The level of RFR measured 5 cm from the antenna of a mobile phone transmitting 600 mW was 0.27 mW/cm2. The average SAR level measured in the nearside eye of the phantom head containing tissue equivalent jellies was 0.7 W/kg for a 600 mW transmit power which is very much less than the spatial peak limit of 8 W/kg underlying the Australian and other national and international RFR exposure standards. (author)

  5. Radio frequency spectroscopy of polarons in ultracold Bose gases

    Science.gov (United States)

    Shashi, Aditya; Grusdt, Fabian; Abanin, Dmitry; Demler, Eugene

    2014-05-01

    Recent experimental advances enabled the realization of mobile impurities immersed in a Bose-Einstein condensate (BEC) of ultracold atoms. We consider impurities with two or more internal hyperfine states, and study their radio-frequency (RF) absorption spectra, which correspond to transitions between two different hyperfine states. We calculate RF spectra for the case when one of the hyperfine states involved interacts with the BEC, while the other state is non-interacting, by performing a non-perturbative resummation of the probabilities of exciting different numbers of phonon modes. We discuss both the direct RF measurement, in which the impurity is initially in an interacting state, and the inverse RF measurement, in which the impurity is initially in a non-interacting state. In the latter case, in order to calculate the RF spectrum, we solve the problem of polaron formation: a mobile impurity dynamically gets dressed by Bogoliubov phonons, using a time-dependent variational ansatz of coherent states.

  6. Observation of radio frequency emissions from electrochemical loading experiments

    International Nuclear Information System (INIS)

    Palladium foil cathodes were electrochemically loaded with deuterium from alkaline solutions of heavy water in specially designed closed calorimeter cells. Here, one cell is described that showed low levels of constant heat (1-7 mW) and radio frequency (RF) emanations, but the RF was not correlated with the heat production. This cell is compared with Pd90Rh10 alloy cathodes that showed excess energy bursts of 2.4-44.3 kJ. In these cells, RF coincident with the bursts was observed peaking at different frequencies from about 450 kHz and extending into the MHz range. Some of the excess energy production in LENR may be in the MHz RF range, which has no conventional explanation in electrochemistry. (author)

  7. Biomedical Monitoring By A Novel Noncontact Radio Frequency Technology Project

    Science.gov (United States)

    Oliva-Buisson, Yvette J. (Compiler)

    2014-01-01

    The area of Space Health and Medicine is one of the NASA's Space Technology Grand Challenges. Space is an extreme environment which is not conducive to human life. The extraterrestrial environment can result in the deconditioning of various human physiological systems and thus require easy to use physiological monitoring technologies in order to better monitor space crews for appropriate health management and successful space missions and space operations. Furthermore, the Space Technology Roadmap's Technology Area Breakdown Structure calls for improvements in research to support human health and performance (Technology Area 06). To address these needs, this project investigated a potential noncontact and noninvasive radio frequency-based technique of monitoring central hemodynamic function in human research subjects in response to orthostatic stress.

  8. Effective Control of Cold Collisions with Radio Frequency Fields

    CERN Document Server

    Ding, Yijue; Greene, Chris H

    2016-01-01

    We study $^{87}$Rb cold collisions in a static magnetic field and a single-color radio frequency (RF) field by employing the multi-channel quantum defect theory in combination with the Floquet method to solve the two-body time-dependent Schr\\"odinger equation. Our results show that RF fields can modify the two-body scattering length by a large scale through Feshbach resonances both in low and high static magnetic field regimes. Such RF induced Feshbach resonances can be applied to quenching experiments or controlling interactions in spinor condensates. Here, we also show that analogous to photo-association, RF fields can also associate cold atoms into molecules at a useful rate.

  9. Radio frequency heating of ceramic windows in fusion applications

    International Nuclear Information System (INIS)

    Ceramic windows will be used as material barriers for radio frequency plasma heating in fusion reactors. This report examines the theory behind rf heating phenomena. Heating calculations are presented for various window materials, thicknesses, wavelengths, and power densities. The most pertinent material properties are loss tangent, thermal conductivity, dielectric constant, strength, and radiation resistance. Calculations indicate that among candidate materials, beryllium oxide offers the most promise because of its large thermal conductivity and relatively low loss tangent and dielectric constant. On the other hand, beryllia is susceptible to neutron damage, and this may adversely affect its electrical properties. Another promising candidate is sapphire, particularly at lower temperatures where the thermal conductivity is high. Fused silica suffers from low thermal conductivity and large positive temperature coefficient for loss tangent, but it may be useful under some conditions. In summary, calculations of heating can lead to elimination of some candidate materials and selection of others for further study

  10. Low radio frequency biased electron cyclotron resonance plasma etching

    Science.gov (United States)

    Samukawa, Seiji; Toyosato, Tomohiko; Wani, Etsuo

    1991-03-01

    A radio frequency (rf) biased electron cyclotron resonance (ECR) plasma etching technology has been developed to realize an efficient ion acceleration in high density and uniform ECR plasma for accurate Al-Si-Cu alloy film etching. In this technology, the substrate is located at the ECR position (875 G position) and the etching is carried out with a 400 kHz rf bias power. This Al-Si-Cu etching technology achieves a high etching rate (more than 5000 A/min), excellent etching uniformity (within ±5%), highly anisotropic etching, and Cu residue-free etching in only Cl2 gas plasma. These etching characteristics are accomplished by the combination of the dense and uniform ECR plasma generation at the ECR position with the efficient accelerated ion flux at the ECR position by using 400 kHz rf bias.

  11. Capacitively coupled radio-frequency discharges in nitrogen at low pressures

    KAUST Repository

    Alves, Luís Lemos

    2012-07-06

    This paper uses experiments and modelling to study capacitively coupled radio-frequency (rf) discharges in pure nitrogen, at 13.56MHz frequency, 0.11 mbar pressures and 230W coupled powers. Experiments performed on two similar (not twin) setups, existing in the LATMOS and the GREMI laboratories, include electrical and optical emission spectroscopy (OES) measurements. Electrical measurements give the rf-applied and the direct-current-self-bias voltages, the effective power coupled to the plasma and the average electron density. OES diagnostics measure the intensities of radiative transitions with the nitrogen second-positive and first-negative systems, and with the 811.5 nm atomic line of argon (present as an actinometer). Simulations use a hybrid code that couples a two-dimensional time-dependent fluid module, describing the dynamics of the charged particles (electrons and positive ions N 2 + and N 4 + ), and a zero-dimensional kinetic module, describing the production and destruction of nitrogen (atomic and molecular) neutral species. The coupling between these modules adopts the local mean energy approximation to define spacetime-dependent electron parameters for the fluid module and to work out spacetime-averaged rates for the kinetic module. The model gives general good predictions for the self-bias voltage and for the intensities of radiative transitions (both average and spatially resolved), underestimating the electron density by a factor of 34. © 2012 IOP Publishing Ltd.

  12. A linear radio frequency plasma reactor for potential and current mapping in a magnetized plasma

    International Nuclear Information System (INIS)

    Langmuir probe measurements in front of high power ion cyclotron resonant frequency antennas are not possible or simply too noisy to be analyzed properly. A linear experiment is a radio frequency (RF) magnetized plasma discharge reactor designed to probe the rectified potential in front of such antennas but at low power level (1 kW) to next improve antenna design and mitigate sheath effects. The maximum magnetic field is 0.1 T, and the RF amplifier can work between 10 kHz and 250 MHz allowing ion cyclotron resonances for argon or helium. The first measurements with no magnetic field are presented here, especially 2D potential maps extracted from the RF compensated probe measurements yield ni ≈ 1015 m−3 and Te ≈ 2 eV for RF power lower than 100 W. Series resonances in the chamber are highlighted and allow to deduce the plasma parameters from a simple equivalent impedance model of the plasma in helium gas. Next studies will be focused on magnetized plasmas and especially magnetized RF sheaths

  13. Langmuir probe and electron energy distribution function measurements of radio frequency ion source

    International Nuclear Information System (INIS)

    In this work a single langmuir probe is used to investigate the low pressure radio-frequency (RF) discharge in argon. The current-voltage characteristic of the probe is used to provide the fundamental plasma parameters, including the electron temperature (Te), electron density (ne), floating potential (vf) and plasma potential (vp).The data are collected at plasma source pressure varying from 1 to 80 mtorr and the discharge powers in the range of 25-250 w. The measurements give an electron density and temperature of ne=1.8 x 1010 to 9.2 x 1011 cm-3 and Te=1.75 to 4.5 eV, respectively. The electron energy distribution function (EEDF) and some elementary processes involved in the RF gas discharge is deduced. The influence of the RF power and plasma cell pressure on ne,Te and vp of the plasma has been examined. The evaluation of the EEDF and its behavior with the pressure in the plasma source is also revealed.

  14. Capacitively coupled radio-frequency discharges in nitrogen at low pressures

    International Nuclear Information System (INIS)

    This paper uses experiments and modelling to study capacitively coupled radio-frequency (rf) discharges in pure nitrogen, at 13.56 MHz frequency, 0.1–1 mbar pressures and 2–30 W coupled powers. Experiments performed on two similar (not twin) setups, existing in the LATMOS and the GREMI laboratories, include electrical and optical emission spectroscopy (OES) measurements. Electrical measurements give the rf-applied and the direct-current-self-bias voltages, the effective power coupled to the plasma and the average electron density. OES diagnostics measure the intensities of radiative transitions with the nitrogen second-positive and first-negative systems, and with the 811.5 nm atomic line of argon (present as an actinometer). Simulations use a hybrid code that couples a two-dimensional time-dependent fluid module, describing the dynamics of the charged particles (electrons and positive ions N2+ and N4+), and a zero-dimensional kinetic module, describing the production and destruction of nitrogen (atomic and molecular) neutral species. The coupling between these modules adopts the local mean energy approximation to define space–time-dependent electron parameters for the fluid module and to work out space–time-averaged rates for the kinetic module. The model gives general good predictions for the self-bias voltage and for the intensities of radiative transitions (both average and spatially resolved), underestimating the electron density by a factor of 3–4. (paper)

  15. Ion Current Density Calculation of the Inductive Radio Frequency Ion Source

    Directory of Open Access Journals (Sweden)

    V.I. Voznyi

    2012-10-01

    Full Text Available A radio-frequency (RF inductive ion source at 27.12 MHz is investigated. With a global model of the argon discharge, plasma density, electron temperature and ion current density of the ion source is calculated in relation to absorbed RF power and gas pressure as a discharge chamber size changes. It is found that ion beam current density grows as the discharge chamber size decreases. Calculations show that in the RF source with a discharge chamber 30 mm in diameter and 35 mm long the ion current density is 40 mA/cm2 at 100 W of absorbed RF power and 7 mTorr of pressure, and agrees well with experimentally measured value of 43 mA/cm2. With decreasing discharge chamber diameter to 15 mm ion current density can reach 85 mA/cm2 at absorbed RF power of 100 W.

  16. The electrical asymmetry effect in geometrically asymmetric capacitive radio frequency plasmas

    International Nuclear Information System (INIS)

    The electrical asymmetry effect (EAE) allows an almost ideal separate control of the mean ion energy, i>, and flux, Γi, at the electrodes in capacitive radio frequency discharges with identical electrode areas driven at two consecutive harmonics with adjustable phase shift, θ. In such geometrically symmetric discharges, a DC self bias is generated as a function of θ. Consequently, i> can be controlled separately from Γi by adjusting the phase shift. Here, we systematically study the EAE in low pressure dual-frequency discharges with different electrode areas operated in argon at 13.56 MHz and 27.12 MHz by experiments, kinetic simulations, and analytical modeling. We find that the functional dependence of the DC self bias on θ is similar, but its absolute value is strongly affected by the electrode area ratio. Consequently, the ion energy distributions change and i> can be controlled by adjusting θ, but its control range is different at both electrodes and determined by the area ratio. Under distinct conditions, the geometric asymmetry can be compensated electrically. In contrast to geometrically symmetric discharges, we find the ratio of the maximum sheath voltages to remain constant as a function of θ at low pressures and Γi to depend on θ at the smaller electrode. These observations are understood by the model. Finally, we study the self-excitation of non-linear plasma series resonance oscillations and its effect on the electron heating.

  17. A computationally assisted spectroscopic technique to measure secondary electron emission coefficients in radio frequency plasmas

    Science.gov (United States)

    Daksha, M.; Berger, B.; Schuengel, E.; Korolov, I.; Derzsi, A.; Koepke, M.; Donkó, Z.; Schulze, J.

    2016-06-01

    A computationally assisted spectroscopic technique to measure secondary electron emission coefficients (γ-CAST) in capacitively-coupled radio-frequency plasmas is proposed. This non-intrusive, sensitive diagnostic is based on a combination of phase resolved optical emission spectroscopy and particle-based kinetic simulations. In such plasmas (under most conditions in electropositive gases) the spatio-temporally resolved electron-impact excitation/ionization rate features two distinct maxima adjacent to each electrode at different times within each RF period. While one maximum is the consequence of the energy gain of electrons due to sheath expansion, the second maximum is produced by secondary electrons accelerated towards the plasma bulk by the sheath electric field at the time of maximum voltage drop across the adjacent sheath. Due to these different excitation/ionization mechanisms, the ratio of the intensities of these maxima is very sensitive to the secondary electron emission coefficient γ. This sensitvity, in turn, allows γ to be determined by comparing experimental excitation profiles and simulation data obtained with various γ-coefficients. The diagnostic, tested here in a geometrically symmetric argon discharge, yields an effective secondary electron emission coefficient of γ =0.066+/- 0.01 for stainless steel electrodes.

  18. A linear radio frequency plasma reactor for potential and current mapping in a magnetized plasma

    Energy Technology Data Exchange (ETDEWEB)

    Faudot, E.; Devaux, S.; Moritz, J.; Heuraux, S.; Molina Cabrera, P.; Brochard, F. [IJL, UMR 7198 CNRS, Universite de Lorraine, 54500 Vandoeuvre les Nancy (France)

    2015-06-15

    Langmuir probe measurements in front of high power ion cyclotron resonant frequency antennas are not possible or simply too noisy to be analyzed properly. A linear experiment is a radio frequency (RF) magnetized plasma discharge reactor designed to probe the rectified potential in front of such antennas but at low power level (1 kW) to next improve antenna design and mitigate sheath effects. The maximum magnetic field is 0.1 T, and the RF amplifier can work between 10 kHz and 250 MHz allowing ion cyclotron resonances for argon or helium. The first measurements with no magnetic field are presented here, especially 2D potential maps extracted from the RF compensated probe measurements yield ni ≈ 10{sup 15} m{sup −3} and Te ≈ 2 eV for RF power lower than 100 W. Series resonances in the chamber are highlighted and allow to deduce the plasma parameters from a simple equivalent impedance model of the plasma in helium gas. Next studies will be focused on magnetized plasmas and especially magnetized RF sheaths.

  19. Radio frequency induced ionized collisional flow model for application at atmospheric pressures

    International Nuclear Information System (INIS)

    We present the development and application of a versatile finite-element method to discretize direct current and radio frequency (rf) induced plasma-sheath dynamics, using multifluid equations. For the former, argon gas is assumed, and the solution is verified by comparison with a theoretical model obtained from the literature. For rf discharges, partially ionized helium gas is considered between two electrodes coated in a dielectric material. The computed solutions for charge densities, the ion velocity and the neutral gas density and crossflow distributions show expected trends. Specifically, ion and electron number densities at the peak discharge current are compared with published numerical results. The derived electric field is utilized with a simple phenomenological model applicable to the transverse velocity in a one-dimensional situation to predict the anticipated hump in the near wall profile. The next step of extending the model, through future work, to two dimensions and for polyphase supply as implemented in realistic configurations is greatly facilitated by the generality of the chosen finite-element method

  20. A novel radio frequency assisted heat pump dryer

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, M.G.; Metaxas, A.C.

    1999-09-01

    This paper compares an experimental heat pump batch dryer with the implementation of volumetric Radio Frequency (RF) heating, in the combination drying of crushed brick particulate. Results are presented showing overall improvements in drying. A simplified mathematical drying model including the RF energy source has been developed using mass and energy conservation, confirming the experimental results. Drying is a widespread, energy intensive industrial unit operation. The economics of a drying process operation largely depend upon the dryers performance and ultimately the cost of energy consumption. To enhance the performance of a drying system, the damp air stream that exits the drying chamber can be recycled to reclaim the enthalpy of evaporation that it carries, by using a heat pump (Hodgett, 1976). However, because the medium that dries is still warm air, this system also suffers from heat transfer limitations, particularly towards the falling drying rate period. Such limitations in drying performance can be overcome with the use of Radio Frequency (RF) energy which generates heat volumetrically within the wet material by the combined mechanisms of dipole rotation and conduction effects which speeds up the drying process (Metaxas et al, 1983). Despite the clear advantages that heat pumps and high frequency heating offer for drying, the combination of these two techniques until recently has not been studied (Kolly et al, 1990; Marshall et al, 1995).A series of experiments carried out comprising a motor driven heat pump which was retro-fitted with the ability of imparting RF energy into a material at various stages of the drying cycle are described and compared with a mathematical model.

  1. Deposition of vertically oriented carbon nanofibers in atmospheric pressure radio frequency discharge

    International Nuclear Information System (INIS)

    Deposition of vertically oriented carbon nanofibers (CNFs) has been studied in an atmospheric pressure radio frequency discharge without dielectric barrier covering the metallic electrodes. When the frequency is sufficiently high so that ions reside in the gap for more than one rf cycle ('trapped ions'), the operating voltage decreases remarkably and the transition from a uniform glow discharge to an arc discharge is suppressed even without dielectric barriers. More importantly, the trapped ions are able to build up a cathodic ion sheath. A large potential drop is created in the sheath between the bulk plasma and the electrode, which is essential for aligning growing CNFs. At the same time, the damage to CNFs due to ion bombardment can be minimized at atmospheric pressure. The primary interest of the present work is in identifying the cathodic ion sheath and investigating how it influences the alignment of growing CNFs in atmospheric pressure plasma-enhanced chemical-vapor deposition. Spectral emission profiles of He (706 nm), Hα (656 nm), and CH (432 nm) clearly showed that a dark space is formed between the cathode layer and the heated bottom electrode. However, increasing the rf power induced the transition to a nonuniform γ-mode discharge which creates intense plasma spots in the dark space. Aligned CNFs can be grown at moderate input power during the initial stage of the deposition process. Catalyst particles were heavily contaminated by precipitated carbon in less than 5 min. Alignment deteriorates as CNFs grow and deposition was virtually terminated by the deactivation of catalyst particles

  2. Glow discharge cleaning of vacuum switch tubes

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, T.; Toya, H. (Mitsubishi Electric Corp., Amagasaki, Hyogo (Japan). Central Research Lab.)

    1991-10-01

    This paper reports that glow discharge cleaning has ben advancing as a means of degassing vacuum chambers constructed for a large accelerator or for nuclear fusion research. To clean the whole surface of parts inside a vacuum switch tube (VST), a new technique is tried which generates glow discharge between the inner electrodes and copper grid surrounding it. Photographic observation reveals that the glow discharge spreads out and cleans the whole surface inside the VST. A breakdown test between the inner electrodes shows the effect of the cleaning with this technique. Higher breakdown voltage between the inner electrodes is attained by performing this glow discharge cleaning in argon rather than hydrogen gas. The difference of the cleaning effect seems to be attributed to that of the energy transfer from ion species to the absorbed molecules and microprotrusions on the surfaces.

  3. 78 FR 19311 - Certain Radio Frequency Identification (“RFID”) Products And Components Thereof; Institution of...

    Science.gov (United States)

    2013-03-29

    ... COMMISSION Certain Radio Frequency Identification (``RFID'') Products And Components Thereof; Institution of... (``RFID'') products and components thereof by reason of infringement of U.S. Patent No. 7,081,819 (``the... sale within the United States after importation of certain radio frequency identification...

  4. Transition characteristics from radio-frequency discharge to arc in hollow cathode configuration

    Institute of Scientific and Technical Information of China (English)

    许建平; 巩春志; 吴明忠; 田修波

    2014-01-01

    The technique ofglow discharges in radio frequency configuration was applied to ignite hollow cathode vacuum arc discharge.The effect of discharge parameters on the building up of hollow cathode arc discharge was investigated.The emission spectrum during the vacuum arc ignition process was measured to disclose the discharge dynamics.There exists a threshold radio frequency power (300 W),beyond which hollow cathode is in γmode discharge status while radio frequency discharge changes into the arc discharge.With the increase of the radio frequency power,the plasma temperature and electronic density increase,and the discharge mode transits more rapidly.The ignition time ofhollow cathode vacuum arc discharge is less than 4 s with a radio frequency power of700 W.

  5. Rapid prototyping for radio-frequency geolocation applications

    Energy Technology Data Exchange (ETDEWEB)

    Briles, S. C. (Scott C.); Arrowood, J. L. (Joseph L.); Braun, T. R. (Thomas R.); Turcotte, D. (Dakx); Fiset, E. (Etienne)

    2004-01-01

    Previous space-to-ground, single-platform geolocation experiments exploiting time-difference-of arrival (TDOA) via interferometry were successful at separating and quantitatively characterizing interfering radio frequency (RF) signals from expected RF transmissions. Much of the success of these experiments rested on the use of embedded processors to perform the required signal processing. The experiments handled data in a 'snapshot' fashion: digitized data was collected, the data was processed via a digital signal processing (DSP) microprocessor to yield differential phase measurements, and these measurements were transmitted to the Earth for geolocation processing. With the utilization of FPGAs (field programmable gate arrays) for the intensive number-crunching algorithms, the processing of streaming real-time data is feasible for bandwidths on the order of 20 MHz. By partitioning the signal processing algorithm so there is a significant reduction in the data rate as data flows through the FPGA, a DSP microprocessor can now be employed to perform further decision-oriented processing on the FPGA output. This hybrid architecture, employing both FPGAs and DSPs, typically requires an expensive and lengthy development cycle. However, the use of graphical development environments with auto-code generation and hardware-in-the-loop testing can result in rapid prototyping for geolocation experiments, which enables adaptation to emerging signals of interest in a cost and time effective manner.

  6. Radio frequency identification enabled wireless sensing for intelligent food logistics.

    Science.gov (United States)

    Zou, Zhuo; Chen, Qiang; Chen, Qing; Uysal, Ismail; Zheng, Lirong

    2014-06-13

    Future technologies and applications for the Internet of Things (IoT) will evolve the process of the food supply chain and create added value of business. Radio frequency identifications (RFIDs) and wireless sensor networks (WSNs) have been considered as the key technological enablers. Intelligent tags, powered by autonomous energy, are attached on objects, networked by short-range wireless links, allowing the physical parameters such as temperatures and humidities as well as the location information to seamlessly integrate with the enterprise information system over the Internet. In this paper, challenges, considerations and design examples are reviewed from system, implementation and application perspectives, particularly with focus on intelligent packaging and logistics for the fresh food tracking and monitoring service. An IoT platform with a two-layer network architecture is introduced consisting of an asymmetric tag-reader link (RFID layer) and an ad-hoc link between readers (WSN layer), which are further connected to the Internet via cellular or Wi-Fi. Then, we provide insights into the enabling technology of RFID with sensing capabilities. Passive, semi-passive and active RFID solutions are discussed. In particular, we describe ultra-wideband radio RFID which has been considered as one of the most promising techniques for ultra-low-power and low-cost wireless sensing. Finally, an example is provided in the form of an application in fresh food tracking services and corresponding field testing results. PMID:24797140

  7. GPU enabled kinetic effects in radio-frequency heating simulation

    Science.gov (United States)

    Green, David; RF-SciDAC Collaboration

    2015-11-01

    In previous work we have demonstrated the iterative addition of parallel kinetic effects to finite-difference frequency-domain simulation of radio-frequency (RF) wave propagation in fusion relevant plasmas. Such iterative addition in configuration space bypasses several of the difficulties with traditional spectral methods for kinetic RF simulation when applied to problems that exhibit non-periodic geometries. Furthermore, the direct numerical integration of particle trajectories in real magnetic field geometries removes violations of the stationary phase approximation inherent in the spectral approach. Here we extend this method to include perpendicular kinetics by relying on the massively parallel capability of GPUs to enable resolution of 3 velocity-space dimensions. We present results for a mode converted ion Bernstein wave scenario in 1-space plus 3-velocity dimensions case relevant to fusion plasmas. This research used resources of the OLCF at ORNL, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725.

  8. Power efficiency improvements with the radio frequency H− ion source

    International Nuclear Information System (INIS)

    CW 13.56 MHz radio frequency-driven H− ion source is under development at the University of Jyväskylä for replacing an existing filament-driven ion source at the MCC30/15 cyclotron. Previously, production of 1 mA H− beam, which is the target intensity of the ion source, has been reported at 3 kW of RF power. The original ion source front plate with an adjustable electromagnet based filter field has been replaced with a new front plate with permanent magnet filter field. The new structure is more open and enables a higher flux of ro-vibrationally excited molecules towards the plasma electrode and provides a better control of the potential near the extraction due to a stronger separation of the main plasma from the plasma electrode. While the original system provided better control over the e−/H− ratio, the new configuration has led to a higher production efficiency of 1 mA H− at 1.75 kW RF power. The latest results and upgrade plans are presented

  9. Fundamental monomeric biomaterial diagnostics by radio frequency signal analysis.

    Science.gov (United States)

    Ji, Jae-Hoon; Shin, Kyeong-Sik; Kang, Shinill; Lee, Soo Hyun; Kang, Ji Yoon; Kim, Sinyoung; Jun, Seong Chan

    2016-08-15

    We present a new diagnostic technique of fundamental monomeric biomaterials that do not rely on any enzyme or chemical reaction. Instead, it only uses radio frequency (RF) signal analysis. The detection and classification of basic biomaterials, such as glucose and albumin, were demonstrated. The device was designed to generate a strong resonance response with glucose solution and fabricated by simple photolithography with PDMS (Polydimethylsiloxane) well. It even was used to detect the level of glucose in mixtures of glucose and albumin and in human serum, and it operated properly and identified the glucose concentration precisely. It has a detection limit about 100μM (1.8mg/dl), and a sensitivity about 58MHz per 1mM of glucose and exhibited a good linearity in human blood glucose level. In addition, the intrinsic electrical properties of biomaterials can be investigated by a de-embedding technique and an equivalent circuit analysis. The capacitance of glucose containing samples exhibited bell-shaped Gaussian dispersion spectra around 2.4GHz. The Albumin solution did not represent a clear dispersion spectra compared to glucose, and the magnitude of resistance and inductance of albumin was higher than that of other samples. Other parameters also represented distinguishable patterns to classify those biomaterials. It leads us to expect future usage of our technique as a pattern-recognizing biosensor. PMID:27111728

  10. Plasma rotation study in Tore Supra radio frequency heated plasmas

    International Nuclear Information System (INIS)

    Toroidal flows are found to improve the performance of the magnetic confinement devices with increase of the plasma stability and confinement. In ITER or future reactors, the torque from NBI should be less important than in present-day tokamaks. Consequently, it is of interest to study other intrinsic mechanisms that can give rise to plasma rotation in order to predict the rotation profile in experiments. Intriguing observations of plasmas rotation have been made in radio frequency (RF) heated plasmas with little or no external momentum injection. Toroidal rotation in both the direction of the plasma current (co-current) and in the opposite direction (counter-current) has been observed depending on the heating schemes and plasma performance. In Tore Supra, most observations in L-mode plasmas have been in the counter-current direction. However, in this thesis, we show that in lower hybrid current drive (LHCD), the core toroidal rotation increment is in co- or counter-current direction depending on the plasma current amplitude. At low plasma current the rotation change is in the co-current direction while at high plasma current, the change is in the counter-current direction. In both low and high plasma current cases, rotation increments are found to increase linearly with the injected LH power. Several mechanisms in competition which can induce co- or counter-current rotation in Tore Supra LHCD plasmas are investigated and typical order of magnitude are discussed in this thesis. (author)

  11. Fast biodiesel production from beef tallow with radio frequency heating

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Shaoyang; Wang, Yifen [Biosystems Engineering Department, Auburn University, 200 Tom E. Corley Building, Auburn, AL 36849-5417 (United States); Oh, Jun-Hyun [Department of Plant Science and Technology, Sangmyung University (Korea, Republic of); Herring, Josh L. [Department of Food and Animal Sciences, Alabama A and M University, Normal, AL 35762 (United States)

    2011-03-15

    Efficient biodiesel production from beef tallow was achieved with radio frequency (RF) heating. A conversion rate of 96.3 {+-} 0.5% was obtained with a NaOH concentration of 0.6% (based on tallow), an RF heating for 5 min, and a methanol/tallow molar ratio of 9:1. Response surface methodology was employed to evaluate the influence of NaOH dose, RF heating time, and methanol/tallow ratio. The alkaline concentration showed the largest positive impact on the conversion rate. Similar fast conversion from canola oil to biodiesel was achieved in our previous work, indicating that RF heating, as an accelerating technique for biodiesel production, had a large applying area. Viscosities of biodiesel products from beef tallow and canola oil were measured as 5.23 {+-} 0.01 and 4.86 {+-} 0.01 mm{sup 2} s{sup -1}, respectively, both meeting the specification in ASTM D6751 (1.9-6.0 mm{sup 2} s{sup -1}). (author)

  12. Fundamental investigations of capacitive radio frequency plasmas: simulations and experiments

    International Nuclear Information System (INIS)

    Capacitive radio frequency (RF) discharge plasmas have been serving hi-tech industry (e.g. chip and solar cell manufacturing, realization of biocompatible surfaces) for several years. Nonetheless, their complex modes of operation are not fully understood and represent topics of high interest. The understanding of these phenomena is aided by modern diagnostic techniques and computer simulations. From the industrial point of view the control of ion properties is of particular interest; possibilities of independent control of the ion flux and the ion energy have been utilized via excitation of the discharges with multiple frequencies. ‘Classical’ dual-frequency (DF) discharges (where two significantly different driving frequencies are used), as well as discharges driven by a base frequency and its higher harmonic(s) have been analyzed thoroughly. It has been recognized that the second solution results in an electrically induced asymmetry (electrical asymmetry effect), which provides the basis for the control of the mean ion energy. This paper reviews recent advances on studies of the different electron heating mechanisms, on the possibilities of the separate control of ion energy and ion flux in DF discharges, on the effects of secondary electrons, as well as on the non-linear behavior (self-generated resonant current oscillations) of capacitive RF plasmas. The work is based on a synergistic approach of theoretical modeling, experiments and kinetic simulations based on the particle-in-cell approach. (paper)

  13. Radio frequency leakage current from unipolar laparoscopic electrocoagulators.

    Science.gov (United States)

    DiNovo, J A

    1983-09-01

    Radio frequency (RF) leakage current has been suspected of causing accidental tissue burns associated with laparoscopic electrocoagulation used for tubal sterilization. A study was done to determine the levels of capacitively coupled RF leakage current from six unipolar laparoscopes manufactured by five companies. Leakage current values ranging from less than 100 mA to over 550 mA were measured at electrosurgical unit power settings of up to 150 w into 1,000 ohms. These levels represent 24-62% of the total electrosurgical current generated by the electrosurgical units. Using a criterion for tissue injury of 100 mA/sq cm applied for ten seconds, leakage current levels exceeding 400 mA are capable of producing burns either at the abdominal wall or to internal organs that accidentally come into contact with the body of the laparoscope. One of the six devices tested had leakage current levels higher than 400 mA at power settings lower than 100 w. Capacitance measurements between the unipolar laparoscope body and the forceps ranged from 53 to 140 picofarads. PMID:6226780

  14. High Radio Frequency Properties and Variability of Brightest Cluster Galaxies

    CERN Document Server

    Hogan, M T; Geach, J E; Grainge, K J B; Hlavacek-Larrondo, J; Hovatta, T; Karim, A; McNamara, B R; Rumsey, C; Russell, H R; Salomé, P; Aller, H D; Aller, M F; Benford, D J; Fabian, A C; Readhead, A C S; Sadler, E M; Saunders, R D E

    2015-01-01

    We consider the high radio frequency (15 GHz - 353 GHz) properties and variability of 35 Brightest Cluster Galaxies (BCGs). These are the most core-dominated sources drawn from a parent sample of more than 700 X-ray selected clusters, thus allowing us to relate our results to the general population. We find that >6.0% of our parent sample (>15.1% if only cool-core clusters are considered) contain a radio-source at 150 GHz of at least 3mJy (~1x10^23 W/Hz at our median redshift of z~0.13). Furthermore, >3.4% of the BCGs in our parent sample contain a peaked component (Gigahertz Peaked Spectrum, GPS) in their spectra that peaks above 2 GHz, increasing to >8.5% if only cool-core clusters are considered. We see little evidence for strong variability at 15 GHz on short (week-month) time-scales although we see variations greater than 20% at 150 GHz over 6-month times-frames for 4 of the 23 sources with multi-epoch observations. Much more prevalent is long-term (year-decade time-scale) variability, with average annua...

  15. Radio frequency integrated circuit design for cognitive radio systems

    CERN Document Server

    Fahim, Amr

    2015-01-01

    This book fills a disconnect in the literature between Cognitive Radio systems and a detailed account of the circuit implementation and architectures required to implement such systems.  Throughout the book, requirements and constraints imposed by cognitive radio systems are emphasized when discussing the circuit implementation details.  In addition, this book details several novel concepts that advance state-of-the-art cognitive radio systems.  This is a valuable reference for anybody with background in analog and radio frequency (RF) integrated circuit design, needing to learn more about integrated circuits requirements and implementation for cognitive radio systems. ·         Describes in detail cognitive radio systems, as well as the circuit implementation and architectures required to implement them; ·         Serves as an excellent reference to state-of-the-art wideband transceiver design; ·         Emphasizes practical requirements and constraints imposed by cognitive radi...

  16. Photonics-based tunable and broadband radio frequency converter

    Science.gov (United States)

    Borges, Ramon Maia; Mazzer, Daniel; Rufino Marins, Tiago Reis; Sodré, Arismar Cerqueira

    2016-03-01

    This paper is regarding the concept and development of a photonics-based tunable and broadband radio frequency converter (PBRC). It employs an external modulation technique to generate and reconfigure its output frequency, a digital circuit to manage the modulators' bias voltages, and an optical interface for connecting it to optical-wireless networks based on radio-over-fiber technology. The proposed optoelectronic device performs photonics-based upconversion and downconversion as a function of the local oscillator frequency and modulators' bias points. Experimental results demonstrate a radiofrequency (RF) carrier conversion with spectral purity over the frequency range from 750 MHz to 6.0 GHz, as well as the integration of the photonics-based converter with an optical backhaul based on a 1.5-km single-mode fiber from a geographically distributed optical network. Low phase noise and distortion absence illustrate its applicability for convergent and reconfigurable optical wireless communications. A potential application relies on the use of PBRC in convergent optical wireless networks to dynamically provide RF carriers as a function of the telecom operator demand and radio propagation environment.

  17. Ultra High-Speed Radio Frequency Switch Based on Photonics

    Science.gov (United States)

    Ge, Jia; Fok, Mable P.

    2015-11-01

    Microwave switches, or Radio Frequency (RF) switches have been intensively used in microwave systems for signal routing. Compared with the fast development of microwave and wireless systems, RF switches have been underdeveloped particularly in terms of switching speed and operating bandwidth. In this paper, we propose a photonics based RF switch that is capable of switching at tens of picoseconds speed, which is hundreds of times faster than any existing RF switch technologies. The high-speed switching property is achieved with the use of a rapidly tunable microwave photonic filter with tens of gigahertz frequency tuning speed, where the tuning mechanism is based on the ultra-fast electro-optics Pockels effect. The RF switch has a wide operation bandwidth of 12 GHz and can go up to 40 GHz, depending on the bandwidth of the modulator used in the scheme. The proposed RF switch can either work as an ON/OFF switch or a two-channel switch, tens of picoseconds switching speed is experimentally observed for both type of switches.

  18. Development of human exposure standards for radio frequency fields

    International Nuclear Information System (INIS)

    Historical aspects of the problem of developing human exposure standards for radio frequency (RF) electromagnetic fields are discussed. It is shown that biological effects and health implications of radiofrequency (RF) electromagnetic fields have been a subject of scientific investigation for more than 50 years. It has become a focus of attention because of the expanded use of RF radiation in the frequency range between 300 MHz and 6 GHz for wireless communication over the past decade. Another cause for the attention is the uncertainty of some observed responses and lack of understanding of the mechanism of interaction of RF electromagnetic fields with biological systems. At present, considerable efforts are devoted to developing and revising RF exposure standards. Each of these efforts should aim to make explicit the philosophy and process by which they reason and decide guidelines for deeming exposure as safe. Furthermore, the reconciliation of philosophies of protection will definitely be an asset, in practice, to those interested in international harmonization of RF exposure standards

  19. Split-aloha algorithm for radio frequency identification system

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Anti-Collision algorithm is one of the most important components of radio frequency identification (RFID) technology, which possesses a key position in the performance of the whole system. ALOHA algorithm is one of the most popular methods to solve the collision problem because of its efficiency and practicability. The grouping method has been developed for enhancing the performance of conventional ALOHA when there are thousands of tags. However, the existing grouping method has limitations in applications due to its rigorous requirements for the estimation of the number of backlog tags or the admirable characteristics of the tags' ID number. Working on the improvement of the grouping methods, we proposed an algorithm named split-ALOHA with a novel grouping method that split tags as a binary tree. The novel grouping method makes it more practicable than the existing grouping methods due to the simplified requirements for tags. Simulations of the proposed algorithm show the superior performance of a linearly increasing of the number of consumed time slots while the number of tags increases. The algorithm performance analysis between split-ALOHA and ALOHA algorithms with other grouping methods has been implemented in a proper way.

  20. Radio Frequency Seeker Modelling and Seeker Filter Design

    Directory of Open Access Journals (Sweden)

    Prashant Vora

    2005-07-01

    Full Text Available Radio frequency seeker model, including receiver angle error noise modelling and filtering of noise from seeker measurement, is presented in this paper. The effects of eclipsing, radar cross section fluctuation, etc on seeker sight-line rate measurement are highlighted. The formulation for colour noise modelling of sight-line rate noise is derived based on the knowledge of seeker receiver angle error noise model. Two Kalman filter configurations for filtering of noise from seeker output have been considered in this paper, based on sight-line rate kinematics and noise characteristic. It has been  observed from the simulation studies that sight-line rate signal varies slowly at higher interceptor-target ranges; with severe colour noise in sight line rate measurement, and therefore higher weightage for noise attenuation is beneficial in Kalman filter configuration. So, kinematic plus state augmentation for colour noise are considered for adequate filtering for higher interceptor-target ranges. Whereas for lower interceptor-target ranges, sight-line rate changes appreciably, which have been tracked by a simplified/modified spherical coordinate model, which uses knowledge of interceptor-target  engagement dynamics. For both the filters, benefits of colour noise modelling and process model augmentation through coloured noise states, for filtering severe colour noise of seeker, has been demonstrated.

  1. Radio frequency interference in solar monitoring using CALLISTO

    Science.gov (United States)

    Abidin, Zamri Zainal; Anim, Norsuzian Mohd; Hamidi, Zety Sharizat; Monstein, Christian; Ibrahim, Zainol Abidin; Umar, Roslan; Shariff, Nur Nafhatun Md; Ramli, Nabilah; Aziz, Noor Aqma Iryani; Sukma, Indriani

    2015-08-01

    Compact Astronomical Low-frequency, Low-cost Instrument for Spectroscopy in Transportable Observatories (CALLISTO) is a global network of spectrometer system with the purpose to observe the Sun's activities. There are 37 stations (using 68 instruments) forming this network from more than 96 countries. We investigate the radio frequency interference (RFI) affecting CALLISTO at these stations. We found that the RFI severely affecting CALLISTO within radio astronomical windows below 870 MHz are in the ranges of 80-110 MHz and 460-500 MHz. We also found that all stations are relatively free from RFI at 270-290 MHz. We investigate the general effect of RFI on detection of solar bursts. We considered type III solar bursts on 10th May, 28th June, 6th July and 8th July, type II on 24th April and type IV on 9th March (all in 2012) in order to measure the percentage of RFI level during solar burst in general. The SNR of the strong solar bursts in for these detections have maxima reaching up to 46.20 (for 6th July).

  2. On creating transport barrier by radio-frequency waves

    International Nuclear Information System (INIS)

    The use of radio frequency (RF) waves in the range of Alfven frequencies is shown to stabilize the drift-ballooning modes in the tokamak if the radial profile of the RF field energy is properly chosen. Stabilization is achieved by the ponder motive force arising due to the radial gradient in the RF field energy. The estimate of the RF power required for this stabilization is found to be rather modest and hence should be easily obtained in the actual experiments. This result therefore shows that the use of the RF waves can create a transport barrier to reduce the loss of particle and energy from the plasma. The new improved mode produced by the RF is expected to have all the advantageous features of the enhanced reverse shear (ERS) modes and at the same time will, unlike the ERS plasma, be sustainable for unlimited period of time and hence should be an attractive choice for the reactor-grade self-sustaining plasma. (author)

  3. A graphical approach to radio frequency quadrupole design

    Science.gov (United States)

    Turemen, G.; Unel, G.; Yasatekin, B.

    2015-07-01

    The design of a radio frequency quadrupole, an important section of all ion accelerators, and the calculation of its beam dynamics properties can be achieved using the existing computational tools. These programs, originally designed in 1980s, show effects of aging in their user interfaces and in their output. The authors believe there is room for improvement in both design techniques using a graphical approach and in the amount of analytical calculations before going into CPU burning finite element analysis techniques. Additionally an emphasis on the graphical method of controlling the evolution of the relevant parameters using the drag-to-change paradigm is bound to be beneficial to the designer. A computer code, named DEMIRCI, has been written in C++ to demonstrate these ideas. This tool has been used in the design of Turkish Atomic Energy Authority (TAEK)'s 1.5 MeV proton beamline at Saraykoy Nuclear Research and Training Center (SANAEM). DEMIRCI starts with a simple analytical model, calculates the RFQ behavior and produces 3D design files that can be fed to a milling machine. The paper discusses the experience gained during design process of SANAEM Project Prometheus (SPP) RFQ and underlines some of DEMIRCI's capabilities.

  4. Radio frequency plasma mediated dry functionalization of multiwall carbon nanotube

    International Nuclear Information System (INIS)

    Highlights: • Plasma functionalization of MWCNT to obtain oxygen and nitrogen containing groups. • Functionalization and removal of amorphous carbon from MWCNT without affecting structural integrity. • Enhanced dispersion in water. • Plasma-CNT interaction mechanism. - Abstract: Surface modification of multiwall carbon nanotubes (MWCNT) was carried out by radio frequency (RF) plasma discharges of oxygen and nitrogen gases to improve their dispersibility. Various oxygen and nitrogen containing functional groups were incorporated as a result of plasma treatment and were confirmed through Fourier transform infrared spectroscopy (FTIR). The effect of plasma treatment on structural properties and morphology changes of MWCNTs was analyzed by Raman, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis. The morphological studies indicate that untreated MWCNT exists as closely packed with highly entangled bundle. During the plasma treatment, MWCNT tubes get disentangled. XRD, Raman and TEM confirmed the absence of any surface damage during plasma treatment. Functionalized carbon nanotubes exhibit high zeta potential values indicating their good dispersibility in water. The method offers a direct and dry means for functionalization of MWCNT without affecting the structure of MWCNT

  5. Compact Superconducting Radio-frequency Accelerators and Innovative RF Systems

    Energy Technology Data Exchange (ETDEWEB)

    Kephart, Robert [Fermilab; Chattopadhyay, Swaapan [Northern Illinois U.; Milton, Stephen [Colorado State U.

    2015-04-10

    We will present several new technical and design breakthroughs that enable the creation of a new class of compact linear electron accelerators for industrial purposes. Use of Superconducting Radio-Frequency (SRF) cavities allow accelerators less than 1.5 M in length to create electron beams beyond 10 MeV and with average beam powers measured in 10’s of KW. These machines can have the capability to vary the output energy dynamically to produce brehmstrahlung x-rays of varying spectral coverage for applications such as rapid scanning of moving cargo for security purposes. Such compact accelerators will also be cost effective for many existing and new industrial applications. Examples include radiation crosslinking of plastics and rubbers, creation of pure materials with surface properties radically altered from the bulk, modification of bulk or surface optical properties of materials, sterilization of medical instruments animal solid or liquid waste, and destruction of organic compounds in industrial waste water effluents. Small enough to be located on a mobile platform, such accelerators will enable new remediation methods for chemical and biological spills and/or in-situ crosslinking of materials. We will describe one current design under development at Fermilab including plans for prototype and value-engineering to reduce costs. We will also describe development of new nano-structured field-emitter arrays as sources of electrons, new methods for fabricating and cooling superconducting RF cavities, and a new novel RF power source based on magnetrons with full phase and amplitude control.

  6. Ultra High-Speed Radio Frequency Switch Based on Photonics.

    Science.gov (United States)

    Ge, Jia; Fok, Mable P

    2015-01-01

    Microwave switches, or Radio Frequency (RF) switches have been intensively used in microwave systems for signal routing. Compared with the fast development of microwave and wireless systems, RF switches have been underdeveloped particularly in terms of switching speed and operating bandwidth. In this paper, we propose a photonics based RF switch that is capable of switching at tens of picoseconds speed, which is hundreds of times faster than any existing RF switch technologies. The high-speed switching property is achieved with the use of a rapidly tunable microwave photonic filter with tens of gigahertz frequency tuning speed, where the tuning mechanism is based on the ultra-fast electro-optics Pockels effect. The RF switch has a wide operation bandwidth of 12 GHz and can go up to 40 GHz, depending on the bandwidth of the modulator used in the scheme. The proposed RF switch can either work as an ON/OFF switch or a two-channel switch, tens of picoseconds switching speed is experimentally observed for both type of switches. PMID:26608349

  7. Low energy booster radio frequency cavity structural analysis

    International Nuclear Information System (INIS)

    The structural design of the Superconducting Super Collider Low Energy Booster (LEB) Radio Frequency (RF) Cavity is very unique. The cavity is made of three different materials which all contribute to its structural strength while at the same time providing a good medium for magnetic properties. Its outer conductor is made of thin walled stainless steel which is later copper plated to reduce the electrical losses. Its tuner housing is made of a fiber reinforced composite laminate, similar to G10, glued to stainless steel plating. The stainless steel of the tuner is slotted to significantly diminish the magnetically-induced eddy currents. The composite laminate is bonded to the stainless steel to restore the structural strength that was lost in slotting. The composite laminate is also a barrier against leakage of the pressurized internal ferrite coolant fluid. The cavity's inner conductor, made of copper and stainless steel, is subjected to high heat loads and must be liquid cooled. The requirements of the Cavity are very stringent and driven primarily by deflection, natural frequency and temperature. Therefore, very intricate finite element analysis was used to complement conventional hand analysis in the design of the cavity. Structural testing of the assembled prototype cavity is planned to demonstrate the compliance of the cavity design to all of its requirements

  8. Radio frequency plasma mediated dry functionalization of multiwall carbon nanotube

    Energy Technology Data Exchange (ETDEWEB)

    Nair, Leena G.; Mahapatra, Anirban S. [Department of Chemistry, Indian Institute of Space Science and Technology, Trivandrum, Kerala 695547 (India); Gomathi, N., E-mail: gomathi@iist.ac.in [Department of Chemistry, Indian Institute of Space Science and Technology, Trivandrum, Kerala 695547 (India); Joseph, K. [Department of Chemistry, Indian Institute of Space Science and Technology, Trivandrum, Kerala 695547 (India); Neogi, S. [Department of Chemical Engineering, Indian Institute of Technology, Kharagpur, West Bengal 721301 (India); Nair, C.P. Reghunadan [Polymers and Special Chemicals Group, Vikram Sarabhai Space Centre, Trivandrum, Kerala 695022 (India)

    2015-06-15

    Highlights: • Plasma functionalization of MWCNT to obtain oxygen and nitrogen containing groups. • Functionalization and removal of amorphous carbon from MWCNT without affecting structural integrity. • Enhanced dispersion in water. • Plasma-CNT interaction mechanism. - Abstract: Surface modification of multiwall carbon nanotubes (MWCNT) was carried out by radio frequency (RF) plasma discharges of oxygen and nitrogen gases to improve their dispersibility. Various oxygen and nitrogen containing functional groups were incorporated as a result of plasma treatment and were confirmed through Fourier transform infrared spectroscopy (FTIR). The effect of plasma treatment on structural properties and morphology changes of MWCNTs was analyzed by Raman, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis. The morphological studies indicate that untreated MWCNT exists as closely packed with highly entangled bundle. During the plasma treatment, MWCNT tubes get disentangled. XRD, Raman and TEM confirmed the absence of any surface damage during plasma treatment. Functionalized carbon nanotubes exhibit high zeta potential values indicating their good dispersibility in water. The method offers a direct and dry means for functionalization of MWCNT without affecting the structure of MWCNT.

  9. Compressive sensing of sparse radio frequency signals using optical mixing.

    Science.gov (United States)

    Valley, George C; Sefler, George A; Shaw, T Justin

    2012-11-15

    We demonstrate an optical mixing system for measuring properties of sparse radio frequency (RF) signals using compressive sensing (CS). Two types of sparse RF signals are investigated: (1) a signal that consists of a few 0.4 ns pulses in a 26.8 ns window and (2) a signal that consists of a few sinusoids at different frequencies. The RF is modulated onto the intensity of a repetitively pulsed, wavelength-chirped optical field, and time-wavelength-space mapping is used to map the optical field onto a 118-pixel, one-dimensional spatial light modulator (SLM). The SLM pixels are programmed with a pseudo-random bit sequence (PRBS) to form one row of the CS measurement matrix, and the optical throughput is integrated with a photodiode to obtain one value of the CS measurement vector. Then the PRBS is changed to form the second row of the mixing matrix and a second value of the measurement vector is obtained. This process is performed 118 times so that we can vary the dimensions of the CS measurement matrix from 1×118 to 118×118 (square). We use the penalized ℓ(1) norm method with stopping parameter λ (also called basis pursuit denoising) to recover pulsed or sinusoidal RF signals as a function of the small dimension of the measurement matrix and stopping parameter. For a square matrix, we also find that penalized ℓ(1) norm recovery performs better than conventional recovery using matrix inversion. PMID:23164876

  10. Mechanical properties of niobium radio-frequency cavities

    International Nuclear Information System (INIS)

    Radio-frequency cavities made of bulk niobium are one of the components used in modern particle accelerators. The mechanical stability is an important aspect of cavity design, which typically relies on finite-element analysis simulations using material properties from tensile tests on sample. This contribution presents the results of strain and resonant frequency measurements as a function of a uniform pressure up to 620 kPa, applied to single-cell niobium cavities with different crystallographic structure, purity and treatments. In addition, burst tests of high-purity multi-cell cavities with different crystallographic structures have been conducted up to the tensile strength of the material. Finite-element analysis of the single-cell cavity geometry is in good agreement with the observed behavior in the elastic regime assuming a Young’s modulus value of 88.5 GPa and a Poisson’s ratio of 0.4, regardless of crystallographic structure, purity or treatment. However, the measured yield strength and tensile strength depend on crystallographic structure, material purity and treatment. In particular, the results from this study show that the mechanical properties of niobium cavities made from ingot material with large crystals are comparable to those of cavities made of fine-grain niobium

  11. Tracking electric field exposure levels through radio frequency dosimetry

    International Nuclear Information System (INIS)

    The radio-frequency (rf) dosimeter developed by the Oak Ridge National Laboratory is a portable, pocket-sized cumulative-dose recording device designed to detect and record the strengths and durations of electric fields present in the work areas of naval vessels. The device measures an integrated dose and records the electric fields that exceed the permissible levels set by the American National Standards Institute. Features of the rf dosimeter include a frequency range of 30 MHz to 10 GHz and a three-dimensional sensor. Data obtained with the rf dosimeter will be used to determine the ambient field-strength profile for shipboard personnel over an extended time. Readings are acquired and averaged over a 6-min period corresponding to the rise time of the core body temperature. These values are stored for up to 6 months, after which the data are transferred to a computer via the dosimeter's serial port. The rf dosimeter should increase knowledge of the levels of electric fields to which individuals are exposed. 5 refs., 4 figs

  12. 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.

  13. Mechanical properties of niobium radio-frequency cavities

    Energy Technology Data Exchange (ETDEWEB)

    Ciovati, G., E-mail: gciovati@jlab.org [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Avenue, Newport News, VA 23606 (United States); Dhakal, P.; Matalevich, J.; Myneni, G. [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Avenue, Newport News, VA 23606 (United States); Schmidt, A.; Iversen, J.; Matheisen, A.; Singer, W. [Deutsches Elektronen-Synchrotron, Notkestraße 85, 22607 Hamburg (Germany)

    2015-08-26

    Radio-frequency cavities made of bulk niobium are one of the components used in modern particle accelerators. The mechanical stability is an important aspect of cavity design, which typically relies on finite-element analysis simulations using material properties from tensile tests on sample. This contribution presents the results of strain and resonant frequency measurements as a function of a uniform pressure up to 620 kPa, applied to single-cell niobium cavities with different crystallographic structure, purity and treatments. In addition, burst tests of high-purity multi-cell cavities with different crystallographic structures have been conducted up to the tensile strength of the material. Finite-element analysis of the single-cell cavity geometry is in good agreement with the observed behavior in the elastic regime assuming a Young’s modulus value of 88.5 GPa and a Poisson’s ratio of 0.4, regardless of crystallographic structure, purity or treatment. However, the measured yield strength and tensile strength depend on crystallographic structure, material purity and treatment. In particular, the results from this study show that the mechanical properties of niobium cavities made from ingot material with large crystals are comparable to those of cavities made of fine-grain niobium.

  14. Plasma Beam Interaction with Negative glow discharge

    International Nuclear Information System (INIS)

    A miniature coaxial gun has been used to study the effect of the energy spectrum of the ejected plasma on the interaction with negative glow region in a normal glow discharge. The peak discharge current flow between the coaxial electrodes was 5.25 K A as a single pulse with pulse duration of 60 MUs. Investigations are carried out with argon gas at pressure 0.4 Torr. The sheath thickness of the ejected plasma from the coaxial discharge was 6 cm with different densities and energies. The spectrum of electron energy varies between 6 eV and 1 eV, while the electron density varies between 5 x 1012 cm -3 and 4x1013 cm -3. The peak velocity of the ejected plasma was 0. 8 x 105 cm sec-1 in the neutral argon atoms. Argon negative glow region used as base plasma has an electron temperature of 2.2 eV and electron density of 6.2 x107 cm-3. It had been found that the velocity of the ejected plasma decreased when it moves in the negative glow region and its mean electron temperature decreased. The results are compared with the theory of beam interaction with cold plasma

  15. Surface Impedance of Superconducting Radio Frequency (SRF) Materials

    Science.gov (United States)

    Xiao, Binping

    Superconducting radio frequency (SRF) technology is widely adopted in particle accelerators. There remain many open questions, however, in developing a systematic understanding of the fundamental behavior of SRF materials, including niobium treated in different ways and various other bulk/thin film materials that are fabricated with different methods under assorted conditions. A facility that can measure the SRF properties of small samples in a range of 2˜40 K temperature is needed in order to fully answer these questions. The Jefferson Lab surface impedance characterization (SIC) system has been designed to attempt to meet this requirement. It consists of a sapphire-loaded cylindrical Nb TE011 cavity at 7.4 GHz with a 50 mm diameter flat sample placed on a non-contacting end plate and uses a calorimetric technique to measure the radio frequency (RF) induced heat on the sample. Driving the resonance to a known field on this surface enables one to derive the surface resistance of a relatively small localized area. TE011 mode identification has been done at room temperature and 4 K, and has been compared with Microwave Studio® and SuperFish simulation results. RF loss mechanisms in the SIC system are under investigation. A VCO phase lock loop system has been used in both CW and pulsed mode. Two calorimeters, with stainless steel and Cu as the thermal path material for high precision and high power versions, respectively, have been designed and commissioned for the SIC system to provide low temperature control and measurement. A power compensation method has been developed to measure the RF induced power on the sample. Simulation and experimental results show that with these two calorimeters, the whole thermal range of interest for SRF materials has been covered, The power measurement error in the interested power range is within 1.2% and 2.7% for the high precision and high power versions, respectively. Temperature distributions on the sample surface for both

  16. The low radio frequency properties of the SNR Kes 79

    Science.gov (United States)

    Castelletti, G.; Giacani, E.; Paron, S.; Dubner, G.

    2009-05-01

    Observations of the supernova remnants (SNRs) at meter and longer wavelengths are powerful tools to differentiate physical processes taking place either in the SNRs (e.g. shock acceleration) or in the interstellar medium intervening along the line of sight towards them (e.g. thermal absorption). Kes 79 (G33.6+0.1) is a Galactic SNR rich in spatial structures in both, radio and X-ray bands, that make it ideal for addressing questions of SNR physics. Its radio morphology at 1.5 Ghz is dominated by a system of two concentric incomplete shells with diameters about 8' and 12'. Chandra observations of Kes 79 reveal many filaments, multiple partial shells, a loop, and a protrusion. The X-ray point source, CXOUJ 185238.6+004020, located close to the geometric center of the remnant was proposed to be the compact stellar remnant formed in the supernova event, although no evidence for a surrounding pulsar wind nebula was found in the X-rays. It has also been suggested that Kes 79 is interacting with a molecular cloud that appears to be partially surrounding its east and southeast borders. In this work we present new high quality images of Kes 79 obtained at low radio frequencies. The observations at 74 and 324 MHz were carried out using multiple-configurations of the Very Large Array (VLA) of the NRAO. We use these data and existing VLA observations at 1.5 GHz to perform an accurate study of the spectral index behaviour over the remnant and its relationship with the properties in the X-ray band of Kes 79. In addition, using HI and CO data from public databases we investigate the influence of the surrounding gas on the morphology of Kes 79.

  17. Radio frequency superconductivity at CERN: a status report

    International Nuclear Information System (INIS)

    Up to 1984 the efforts in superconducting (s.c.) cavity development at CERN were mainly concentrated on 500 MHz cavities, leading to the test of a 5-cell, 500 MHz cavity at PETRA. The results confirmed that the achievable accelerating fields do not decrease at lower frequencies as strongly as previously suspected. Therefore, it was decided in 1984 to concentrate efforts on 352 MHz cavities. This frequency choice is suggested by the fact that LEP will be equipped at the beginning with 128 Cu cavities at 352 MHz which will bring up energies to 55 GeV/beam [5]. There is an obvious interest to install at a later stage s.c. cavities with the same frequency and to use at maximum the existing installation of radio frequency (r.f.) power sources. With the installed r.f. power of 16 MW, LEP could be upgraded to ∼ 90 GeV by using s.c. cavities. This will require the construction, testing and installation of several hundred of s.c. cavities, therefore arguments of economy and reliability are of outstanding importance. The LEP program asks for many additional items and substantial work has gone into the development, construction and testing of cryostats, main couplers, Higher-Order Mode (HOM) couplers and frequency tuners. Besides the main line based on Nb-cavities another development has been pursued and that is the deposition of a thin niobium layer on copper cavities. Results look very promising but more efforts will be needed to reach the same level of know-how as for Nb cavities. 34 references, 7 figures, 2 tables

  18. Radio Frequency Characteristics of Printed Meander Inductors and Interdigital Capacitors

    Science.gov (United States)

    Myllymaki, Sami; Teirikangas, Merja; Nelo, Mikko; Tulppo, Joel; Sobociński, Maciej; Juuti, Jari; Jantunen, Heli; Sloma, Marcin; Jakubowska, Malgorzata

    2013-05-01

    Radio frequency (RF) characterizations of printed silver ink inductors manufactured at low (150 °C) and high (850 °C) temperatures and interdigital capacitors manufactured at high (850 °C) temperatures were carried out in the 500 MHz to 6 GHz range. The S-parameter responses of the components were measured with a probe station and an Agilent 8510C network analyzer. Electrical parameters such as inductance, capacitance, and a quality factor were estimated from experimental results and numerical calculation. Component parameters are dependent on physical dimensions and material properties. The components were created in a 4 ×4 mm2 area with line widths/gaps of 500/500, 250/250, and 200/200 µm. Windings in the coils varied from 2 to 5 turns and finger counts in the capacitors, from 5 to 11 within the defined area and line widths. As a result, low-T-cured (150 °C) silver ink meander line inductors achieved 8 to 18 nH inductances at 1 and 2 GHz with a quality value of 10-25. High-T-cured (850 °C) silver ink meander line inductors had 6-15 nH inductances and quality values were around 100, indicating a conductivity challenge with low-T-cured inks. Interdigital capacitors with 1 to 4 pF capacitances and sufficient quality values were created. A low-loss BaTiO3 coating was printed over the interdigital capacitors; they exhibited suitable electrical characteristics to allow decreasing the physical size of the component.

  19. Status of radio frequency quadrupole accelerator at IUAC, New Delhi

    International Nuclear Information System (INIS)

    As part of the accelerator augmentation program at IUAC, a High Current Injector (HCI) is being developed to inject highly charged ions into the superconducting LINAC. The HCI consists of a superconducting (High TC) ECR source, producing the high currents of highly charged ions. The ion beams produced will be injected into a Radio Frequency Quadrupole Accelerator (RFQ) and be accelerated to 180 keV/u. RF power of about 100 kW at 48.5 MHz will be fed to the RFQ during its actual working. The ions will be further accelerated by a Drift Tube Linac (DTL), before being further velocity matched with a low beta cavity into the superconducting LINAC. RFQ at IUAC is a four rod cavity structure having individual demountable copper vanes held on vane posts with a total vane length of 2.536 m and a minimum aperture of 12mm. The vane posts hold twenty nos. of vanes. Water will flow into vanes through the vane posts. The copper plated stainless steel vacuum housing has been divided into two chambers for the ease of fabrication and copper plating. The RFQ stand has provision for alignment in all the three axes. After successfully validating all the electrical and mechanical design parameters on a prototype RFQ, the fabrication of final RFQ has been completed. Initial assembly to check the mechanical accuracies was carried out. Low power RF tests were conducted to validate the design parameters. The resonance frequency of the RFQ was measured as 44.12 MHz and Q value was measured ∼ 5500. The final assembly is in progress. This paper details the present status and future plan of RFQ. (author)

  20. Radio-frequency quadrupole: a new linear accelerator

    International Nuclear Information System (INIS)

    In many Laboratories, great emphasis now is placed on the development of linear accelerators with very large ion currents. To achieve this goal, a primary concern must be the low-velocity part of the accelerator, where the current limit is determined and where most of the emittance growth occurs. The use of magnetic focusing, the conflicting requirements in the choice of linac frequency, and the limitations of high-voltage dc injectors, have tended to produce low-velocity designs that limit overall performance. The radio-frequency quadrupole (RFQ) linear accelerator, invented in the Soviet Union and developed at Los Alamos, offers an attractive solution to many of these low-velocity problems. In the RFQ, the use of RF electric fields for radial focusing, combined with special programming of the bunching, allows high-current dc beams to be captured and accelerated with only small beam loss and low radial emittance growth. Advantages of the RFQ linac include a low injection energy (20 to 50 keV for protons) and a final energy high enough so the beam can be further accelerated with high efficiency in a Wideroee or Alvarez linac. These properties have been confirmed at Los Alamos in a highly successful experimental test performed during the past year. The success of this test and the advances in RFQ design procedures have led to the adoption of this linac for a wide range of applications. The beam-dynamics parameters of three RFQ systems are described. These are the final design for the protytype test of the Fusion Materials Irradiation Test (FMIT) accelerator, the final design for the prototype test of the Pion Generator for Medical Irradiations (PIGMI), and an improved low-velocity linac for heavy ion fusion

  1. Radio-frequency spectroscopy of polarons in ultracold Bose gases

    Science.gov (United States)

    Shashi, Aditya; Grusdt, Fabian; Abanin, Dmitry A.; Demler, Eugene

    2014-05-01

    Recent experimental advances enabled the realization of mobile impurities immersed in a Bose-Einstein condensate (BEC) of ultracold atoms. Here, we consider impurities with two or more internal hyperfine states, and study their radio-frequency (rf) absorption spectra, which correspond to transitions between two different hyperfine states. We calculate rf spectra for the case when one of the hyperfine states involved interacts with the BEC, while the other state is noninteracting, by performing a nonperturbative resummation of the probabilities of exciting different numbers of phonon modes. In the presence of interactions, the impurity gets dressed by Bogoliubov excitations of the BEC, and forms a polaron. The rf signal contains a δ-function peak centered at the energy of the polaron measured relative to the bare impurity transition frequency with a weight equal to the amount of bare impurity character in the polaron state. The rf spectrum also has a broad incoherent part arising from the background excitations of the BEC, with a characteristic power-law tail that appears as a consequence of the universal physics of contact interactions. We discuss both the direct rf measurement, in which the impurity is initially in an interacting state, and the inverse rf measurement, in which the impurity is initially in a noninteracting state. In the latter case, in order to calculate the rf spectrum, we solve the problem of polaron formation: a mobile impurity is suddenly introduced in a BEC, and dynamically gets dressed by Bogoliubov phonons. Our solution is based on a time-dependent variational ansatz of coherent states of Bogoliubov phonons, which becomes exact when the impurity is localized. Moreover, we show that such an ansatz compares well with a semiclassical estimate of the propagation amplitude of a mobile impurity in the BEC. Our technique can be extended to cases when both initial and final impurity states are interacting with the BEC.

  2. Scattering of radio frequency waves by blobs in tokamak plasmas

    International Nuclear Information System (INIS)

    The density fluctuations and blobs present in the edge region of magnetic fusion devices can scatter radio frequency (RF) waves through refraction, reflection, diffraction, and coupling to other plasma waves. This, in turn, affects the spectrum of the RF waves and the electromagnetic power that reaches the core of the plasma. The usual geometric optics analysis of RF scattering by density blobs accounts for only refractive effects. It is valid when the amplitude of the fluctuations is small, of the order of 10%, compared to the background density. In experiments, density fluctuations with much larger amplitudes are routinely observed, so that a more general treatment of the scattering process is needed. In this paper, a full-wave model for the scattering of RF waves by a blob is developed. The full-wave approach extends the range of validity well beyond that of geometric optics; however, it is theoretically and computationally much more challenging. The theoretical procedure, although similar to that followed for the Mie solution of Maxwell's equations, is generalized to plasmas in a magnetic field. Besides diffraction and reflection, the model includes coupling to a different plasma wave than the one imposed by the external antenna structure. In the model, it is assumed that the RF waves interact with a spherical blob. The plasma inside and around the blob is cold, homogeneous, and imbedded in a uniform magnetic field. After formulating the complete analytical theory, the effect of the blob on short wavelength electron cyclotron waves and longer wavelength lower hybrid waves is studied numerically

  3. Scattering of radio frequency waves by blobs in tokamak plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Ram, Abhay K. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Hizanidis, Kyriakos; Kominis, Yannis [School of Electrical and Computer Engineering, National Technical University of Athens, Association EURATOM-Hellenic Republic, Athens, GR-15773 (Greece)

    2013-05-15

    The density fluctuations and blobs present in the edge region of magnetic fusion devices can scatter radio frequency (RF) waves through refraction, reflection, diffraction, and coupling to other plasma waves. This, in turn, affects the spectrum of the RF waves and the electromagnetic power that reaches the core of the plasma. The usual geometric optics analysis of RF scattering by density blobs accounts for only refractive effects. It is valid when the amplitude of the fluctuations is small, of the order of 10%, compared to the background density. In experiments, density fluctuations with much larger amplitudes are routinely observed, so that a more general treatment of the scattering process is needed. In this paper, a full-wave model for the scattering of RF waves by a blob is developed. The full-wave approach extends the range of validity well beyond that of geometric optics; however, it is theoretically and computationally much more challenging. The theoretical procedure, although similar to that followed for the Mie solution of Maxwell's equations, is generalized to plasmas in a magnetic field. Besides diffraction and reflection, the model includes coupling to a different plasma wave than the one imposed by the external antenna structure. In the model, it is assumed that the RF waves interact with a spherical blob. The plasma inside and around the blob is cold, homogeneous, and imbedded in a uniform magnetic field. After formulating the complete analytical theory, the effect of the blob on short wavelength electron cyclotron waves and longer wavelength lower hybrid waves is studied numerically.

  4. Self-organized behaviour of radio-frequency plasmoids

    International Nuclear Information System (INIS)

    As recent studies showed, well-located complex space charge configurations (CSCC) generated in plasma subjected to a sufficient strong external constraint exhibit a proper dynamics. A CSCC appears in HF plasma as a radio frequency plasmoid (RFP). Its self-consistence is ensured by a double layer (DL) self-assembled at its border. Under certain experimental conditions, the RFP reveals a proper dynamics, evidenced by periodic variations of the light emission and by a modulation of the HF field. Varying the amount of the energy injected in the HF discharge one can evidence the transition of the RFP between different states. We report experimental observations on the dynamics of the RFP depending on the external constraints applied to the HF discharge. A tentatively explanation of the RFP phenomenon from the viewpoint of a self-organisation phenomena in plasma is established. A generalized self-organization scenario based on experimental observations on the dynamics of a RFP is drawn. As a general rule of self-organization process, the major importance for the system evolution of energy pumping, anomalous entropy production and anomalous entropy expulsion processes and the relation between their rates are emphasized. The proposed scenario outlines the self-organization stages of CSCC bordered by DLs and can also describe the transitions to more elevated levels of self-organization. The backward transitions between these levels are also described. The scenario proposes an explanation of the dynamics of these structures, considering their behaviour as being periodic, intermittent or even chaotic. Taking into account the similarities between the RFP and CSCCs formed in DC plasma devices, we consider that the conclusions drawn and the proposed self-organization proposed could be applied to all CSCC bordered by DL. (authors)

  5. Effect of O2 gas partial pressure on mechanical properties of Al2O3 films deposited by inductively coupled plasma-assisted radio frequency magnetron sputtering

    International Nuclear Information System (INIS)

    The effect of O2 partial pressure on the mechanical properties of Al2O3 films is studied. Using films prepared by inductively coupled plasma-assisted radio frequency magnetron sputtering, the deposition rate of Al2O3 decreases rapidly when oxygen is added to the argon sputtering gas. The internal stresses in the films are compressive, with magnitude decreasing steeply from 1.6 GPa for films sputtered in pure argon gas to 0.5 GPa for films sputtered in argon gas at an O2 partial pressure of 0.89 × 10−2 Pa. Stress increases gradually with increasing O2 partial pressure. Using a nanoindentation tester with a Berkovich indenter, film hardness was measured to be about 14 GPa for films sputtered in pure argon gas. Hardness decreases rapidly on the addition of O2 gas, but increases when the O2 partial pressure is increased. Adhesion, measured using a Vickers microhardness tester, increases with increasing O2 partial pressure. Electron probe microanalyzer measurements reveal that the argon content of films decreases with increasing O2 partial pressure, whereas the O to Al composition ratio increases from 1.15 for films sputtered in pure argon gas to 1.5 for films sputtered in argon gas at O2 partial pressures over 2.4 × 10−2 Pa. X-ray diffraction measurements reveal that films sputtered in pure argon gas have an amorphous crystal structure, whereas γ-Al2O3 is produced for films sputtered in argon gas with added O2 gas. Atomic force microscopy observations reveal that the surface topography of sputtered Al2O3 films changes from spherical to needlelike as O2 partial pressure is increased. Fracture cross sections of the films observed by scanning electron microscopy reveal that the film morphology exhibits no discernible features at all O2 partial pressures.

  6. Excitation dynamics in electrically asymmetric capacitively coupled radio frequency discharges: experiment, simulation, and model

    International Nuclear Information System (INIS)

    The symmetry of capacitively coupled radio frequency (CCRF) discharges can be controlled electrically by applying a fundamental frequency and its second harmonic with fixed but adjustable phase shift θ between the driving voltages to one electrode. In such a discharge a variable dc self-bias η is generated as an almost linear function of θ for 00 ≤ θ ≤ 900 via the Electrical Asymmetry Effect. The control parameter for η and the discharge symmetry is θ. Here electron dynamics in electrically asymmetric geometrically symmetric dual frequency discharges operated in argon at 13.56 and 27.12 MHz is investigated experimentally by a particle-in-cell simulation and by an analytical model. The electron dynamics is probed by the electron impact excitation rate of energetic electrons from the ground state into highly excited levels. At high pressures (collisional sheaths) the excitation dynamics is found to work differently compared with conventional CCRF discharges. Unlike in classical discharges the maxima of the time modulated excitation at the powered and grounded electrode within one low frequency period will be similar (symmetric excitation), if η is strong at θ ∼ 00, 900, and significantly different (asymmetric excitation), if η ∼ 0 V at θ ∼ 450. At low pressures (collisionless sheaths) the excitation dynamics works similar to classical discharges, i.e. the excitation will be asymmetric, if η is strong, and symmetric, if η ∼ 0 V. This dynamics is understood in the frame of an analytical model, which provides a more detailed insight into electron heating in CCRF discharges and could be applied to other types of capacitive RF discharges as well.

  7. 78 FR 49529 - Radio Frequency Wireless Technology in Medical Devices; Guidance for Industry and Food and Drug...

    Science.gov (United States)

    2013-08-14

    ... HUMAN SERVICES Food and Drug Administration (formerly Docket No. 2006D-0504) Radio Frequency Wireless... considerations related to the incorporation and integration of radio frequency (RF) wireless technology in... service, coexistence, security, and electromagnetic compatibility, and provides recommendations...

  8. Application of microwave/radio frequency and radio frequency/magnetron sputtering techniques in polyurethane surface modification

    Directory of Open Access Journals (Sweden)

    W. Kaczorowski

    2009-12-01

    Full Text Available Purpose: The aim of the study is the analysis of the possibilities of application of MW/RF PACVD and RF PACVD/MS systems in polyurethane surface modification.Design/methodology/approach: As the substrates samples made out of the biocompatibile polyurethane were used. Modifications were performed in MW/RF PACVD and RF PACVD/MS reactors using different gases and process parameters. Topography, thickness and contact angle were measured using Atomic Force Microscopy, Profilometry and Contact Angle Measuring Instrument.Findings: Optimal plasma parameters ensuring deposition of carbon layers without surface degradation were worked out. Deposited layers were less than 500 nm thick and presented the wetting angle value more than 90º. During the examinations the influence of the gas atmosphere and process parameters used for the preliminary substrates modification were investigated. Obtained results prove the possibility of application of MW/RF PACVD and RF PACVD/MS techniques in deposition of carbon-based coatings on polyurethane substrates used for artificial heart chambers manufacturing.Research limitations/implications: Modification of polymer surface has to be conducted at low temperatures, up to 100ºC. Unfortunately not all CVD and PVD methods used in this field guarantee the adequate adhesion of manufactured layers deposited in such low temperatures. So far the most promising results were obtained with use of PLD (pulsed laser deposition techniques. However application of MW (microwave low temperature plasma source and combination of magnetron sputtering technique with RF (radio frequency plasma source seems to be equally interesting techniques.Originality/value: Optimization of carbon layers deposition techniques on polyurethane substrates can be helpful in improvement of modern artificial heart chambers construction. All investigation results obtained in his field attend to work out the new generation of cardiosurgical implants within the

  9. Radio Frequency Station - Beam Dynamics Interaction in Circular Accelerators

    International Nuclear Information System (INIS)

    The longitudinal beam dynamics in circular accelerators is mainly defined by the interaction of the beam current with the accelerating Radio Frequency (RF) stations. For stable operation, Low Level RF (LLRF) feedback systems are employed to reduce coherent instabilities and regulate the accelerating voltage. The LLRF system design has implications for the dynamics and stability of the closed-loop RF systems as well as for the particle beam, and is very sensitive to the operating range of accelerator currents and energies. Stability of the RF loop and the beam are necessary conditions for reliable machine operation. This dissertation describes theoretical formalisms and models that determine the longitudinal beam dynamics based on the LLRF implementation, time domain simulations that capture the dynamic behavior of the RF station-beam interaction, and measurements from the Positron-Electron Project (PEP-II) and the Large Hadron Collider (LHC) that validate the models and simulations. These models and simulations are structured to capture the technical characteristics of the system (noise contributions, non-linear elements, and more). As such, they provide useful results and insight for the development and design of future LLRF feedback systems. They also provide the opportunity to study diverse longitudinal beam dynamics effects such as coupled-bunch impedance driven instabilities and single bunch longitudinal emittance growth. Coupled-bunch instabilities and RF station power were the performance limiting effects for PEP-II. The sensitivity of the instabilities to individual LLRF parameters, the effectiveness of alternative operational algorithms, and the possible tradeoffs between RF loop and beam stability were studied. New algorithms were implemented, with significant performance improvement leading to a world record current during the last PEP-II run of 3212 mA for the Low Energy Ring. Longitudinal beam emittance growth due to RF noise is a major concern for LHC

  10. Radio Frequency Station - Beam Dynamics Interaction in Circular Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Mastoridis, Themistoklis [Stanford Univ., CA (United States)

    2010-08-01

    The longitudinal beam dynamics in circular accelerators is mainly defined by the interaction of the beam current with the accelerating Radio Frequency (RF) stations. For stable operation, Low Level RF (LLRF) feedback systems are employed to reduce coherent instabilities and regulate the accelerating voltage. The LLRF system design has implications for the dynamics and stability of the closed-loop RF systems as well as for the particle beam, and is very sensitive to the operating range of accelerator currents and energies. Stability of the RF loop and the beam are necessary conditions for reliable machine operation. This dissertation describes theoretical formalisms and models that determine the longitudinal beam dynamics based on the LLRF implementation, time domain simulations that capture the dynamic behavior of the RF station-beam interaction, and measurements from the Positron-Electron Project (PEP-II) and the Large Hadron Collider (LHC) that validate the models and simulations. These models and simulations are structured to capture the technical characteristics of the system (noise contributions, non-linear elements, and more). As such, they provide useful results and insight for the development and design of future LLRF feedback systems. They also provide the opportunity to study diverse longitudinal beam dynamics effects such as coupled-bunch impedance driven instabilities and single bunch longitudinal emittance growth. Coupled-bunch instabilities and RF station power were the performance limiting effects for PEP-II. The sensitivity of the instabilities to individual LLRF parameters, the effectiveness of alternative operational algorithms, and the possible tradeoffs between RF loop and beam stability were studied. New algorithms were implemented, with significant performance improvement leading to a world record current during the last PEP-II run of 3212 mA for the Low Energy Ring. Longitudinal beam emittance growth due to RF noise is a major concern for LHC

  11. The Radio Frequency Health Node Wireless Sensor System

    Science.gov (United States)

    Valencia, J. Emilio; Stanley, Priscilla C.; Mackey, Paul J.

    2009-01-01

    The Radio Frequency Health Node (RFHN) wireless sensor system differs from other wireless sensor systems in ways originally intended to enhance utility as an instrumentation system for a spacecraft. The RFHN can also be adapted to use in terrestrial applications in which there are requirements for operational flexibility and integrability into higher-level instrumentation and data acquisition systems. As shown in the figure, the heart of the system is the RFHN, which is a unit that passes commands and data between (1) one or more commercially available wireless sensor units (optionally, also including wired sensor units) and (2) command and data interfaces with a local control computer that may be part of the spacecraft or other engineering system in which the wireless sensor system is installed. In turn, the local control computer can be in radio or wire communication with a remote control computer that may be part of a higher-level system. The remote control computer, acting via the local control computer and the RFHN, cannot only monitor readout data from the sensor units but can also remotely configure (program or reprogram) the RFHN and the sensor units during operation. In a spacecraft application, the RFHN and the sensor units can also be configured more nearly directly, prior to launch, via a serial interface that includes an umbilical cable between the spacecraft and ground support equipment. In either case, the RFHN wireless sensor system has the flexibility to be configured, as required, with different numbers and types of sensors for different applications. The RFHN can be used to effect realtime transfer of data from, and commands to, the wireless sensor units. It can also store data for later retrieval by an external computer. The RFHN communicates with the wireless sensor units via a radio transceiver module. The modular design of the RFHN makes it possible to add radio transceiver modules as needed to accommodate additional sets of wireless sensor

  12. Radio Frequency Station - Beam Dynamics Interaction in Circular Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Mastoridis, Themistoklis; /Stanford U., Elect. Eng. Dept. /SLAC

    2011-03-01

    The longitudinal beam dynamics in circular accelerators is mainly defined by the interaction of the beam current with the accelerating Radio Frequency (RF) stations. For stable operation, Low Level RF (LLRF) feedback systems are employed to reduce coherent instabilities and regulate the accelerating voltage. The LLRF system design has implications for the dynamics and stability of the closed-loop RF systems as well as for the particle beam, and is very sensitive to the operating range of accelerator currents and energies. Stability of the RF loop and the beam are necessary conditions for reliable machine operation. This dissertation describes theoretical formalisms and models that determine the longitudinal beam dynamics based on the LLRF implementation, time domain simulations that capture the dynamic behavior of the RF station-beam interaction, and measurements from the Positron-Electron Project (PEP-II) and the Large Hadron Collider (LHC) that validate the models and simulations. These models and simulations are structured to capture the technical characteristics of the system (noise contributions, non-linear elements, and more). As such, they provide useful results and insight for the development and design of future LLRF feedback systems. They also provide the opportunity to study diverse longitudinal beam dynamics effects such as coupled-bunch impedance driven instabilities and single bunch longitudinal emittance growth. Coupled-bunch instabilities and RF station power were the performance limiting effects for PEP-II. The sensitivity of the instabilities to individual LLRF parameters, the effectiveness of alternative operational algorithms, and the possible tradeoffs between RF loop and beam stability were studied. New algorithms were implemented, with significant performance improvement leading to a world record current during the last PEP-II run of 3212 mA for the Low Energy Ring. Longitudinal beam emittance growth due to RF noise is a major concern for LHC

  13. 78 FR 43916 - Certain Radio Frequency Identification (RFID) Products and Components Thereof; Commission...

    Science.gov (United States)

    2013-07-22

    ...,690,264. 78 FR 19311 (Mar. 29, 2013). The respondents are Federal Signal Corporation of Oakbrook... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Certain Radio Frequency Identification (RFID) Products and Components Thereof;...

  14. Radio-frequency transparent demodulation for broadband hybrid wireless-optical links

    DEFF Research Database (Denmark)

    Zibar, Darko; Sambaraju, Rakesh; Alemany, Ruben;

    2010-01-01

    A novel demodulation technique which is transparent to radio-frequency (RF) carrier frequency is presented and experimentally demonstrated for multigigabit wireless signals. The presented demodulation technique employs optical single-sideband filtering, coherent detection, and baseband digital...

  15. An L-Band Radio Frequency Interference (RFI) Detection and Mitigation Testbed Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Radio Frequency Interference (RFI) can render microwave radiometer measurements useless. We have proposed a method and an architecture that can be used to identify...

  16. Radio-frequency wave trajectories for current drive in tokamak reactors

    International Nuclear Information System (INIS)

    Detailed ray tracing calculations were carried out for three modes of waveguide-launched radio-frequency waves for tokamak reactor parameters to evaluate their applicability for steady state current drive. The merits and demerits of each mode are discussed

  17. Investigation of beech wood modified by radio-frequency discharge plasma

    Czech Academy of Sciences Publication Activity Database

    Novák, I.; Popelka, A.; Špitalský, Z.; Mičušík, M.; Omastová, M.; Valentin, M.; Sedliačik, J.; Janigová, I.; Kleinová, A.; Šlouf, Miroslav

    2015-01-01

    Roč. 119, September (2015), s. 88-94. ISSN 0042-207X Institutional support: RVO:61389013 Keywords : radio-frequency plasma * beech wood * adhesive properties Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.858, year: 2014

  18. Radio-frequency wave trajectories for current drive in tokamak reactors

    Energy Technology Data Exchange (ETDEWEB)

    Wong, K.L.; Ono, M.

    1982-12-01

    Detailed ray tracing calculations were carried out for three modes of waveguide-launched radio-frequency waves for tokamak reactor parameters to evaluate their applicability for steady state current drive. The merits and demerits of each mode are discussed.

  19. A C-Band Radio Frequency Interference (RFI) Detection and Mitigation Testbed Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Radio Frequency Interference (RFI) can render microwave radiometer measurements useless. We propose a method and an architecture that can be used to identify...

  20. Surface Planar Ion Chip for Linear Radio-Frequency Paul Traps

    Institute of Scientific and Technical Information of China (English)

    WAN Jin-Yin; QU Qiu-Zhi; ZHOU Zi-Chao; LI Xiao-Lin; WANG Yu-Zhu; LIU Liang

    2007-01-01

    We propose a surface planar ion chip which forms a linear radio frequency Paul ion trap. The electrodes reside in the two planes of a chip, and the trap axis is located above the chip surface. Its electric field and potential distribution are similar to the standard linear radio frequency Paul ion trap. This ion trap geometry may be greatly meaningful for quantum information processing.

  1. Radio-Frequency Field-Induced Quantum Interference Effects in Cold Atoms

    Institute of Scientific and Technical Information of China (English)

    龙全; 周蜀渝; 周善钰; 王育竹

    2001-01-01

    We propose constructing a quantum interference configuration for cold atoms in a magneto-optical trap by applying a radio frequency field, which coherently couples adjacent Zeeman sublevels, in combination with a repumping laser field. One effect of this interference is that a dip exists in the absorption of the repumping light when the radio frequency is scanned. Our prediction has been indirectly detected through the fluorescence of cold atoms in a preliminary experiment.

  2. Implementation of a Digital Radio Frequency Memory in a Xilinx Virtex-4 FPGA

    OpenAIRE

    Gustafsson, Kristian

    2005-01-01

    Digital Radio Frequency Memory (DRFM) is a technique widely used by the defense industry in, for example, electronic countermeasure equipment for generating false radar targets. The purpose of the DRFM technique is to use high-speed sampling to digitally store and recreate radio frequency and microwave signals. At Saab Bofors Dynamics AB the technique is used, among others, in the Electronic Warfare Simulator (ELSI). The DRFM technique is implemented in a full-custom ASIC circuit that has bee...

  3. Radio frequency identification-enabled capabilities in a healthcare context: An exploratory study.

    Science.gov (United States)

    Hornyak, Rob; Lewis, Mark; Sankaranarayan, Balaji

    2016-09-01

    Increasingly, the adoption and use of radio frequency identification systems in hospital settings is gaining prominence. However, despite the transformative impact that radio frequency identification has in healthcare settings, few studies have examined how and why this change may occur. The purpose of this study is to systematically understand how radio frequency identification can transform work practices in an operational process that directly impacts cost and operational efficiency and indirectly contributes to impacting patient safety and quality of care. We leverage an interdisciplinary framework to explore the contextual characteristics that shape the assimilation of radio frequency identification in healthcare settings. By linking the use of radio frequency identification with specific contextual dimensions in healthcare settings, we provide a data-driven account of how and why radio frequency identification can be useful in inventory management in this setting. In doing so, we also contribute to recent work by information systems scholars who argue for a reconfiguration of conventional assumptions regarding the role of technology in contemporary organizations. PMID:25786775

  4. Non-invasive temperature monitoring using small coils during radio-frequency heating

    International Nuclear Information System (INIS)

    In hyperthermia treatment of malignant tumors, thermal tissue injury increases drastically with every degree of increase in the tissue temperature above 42.5 .deg. C Accurate temperature monitoring during hyperthermia is important. Therefore, we developed a non-invasive method to monitor the tissue temperature during radio-frequency hyperthermia by detecting the magnetic field induced by the radio-frequency currents that flow through the heated tissue. This technique uses small multi-channel coil antennas to detect radio-frequency currents and generates two-dimensional distribution in the tissue. A rectifying circuit was connected to each coil antenna, and the current was converted with a fixed resistance into voltage. Since the voltage output from each antenna was attenuated at 1/2pr (r: distance from the radio-frequency current), single-peaked projection data were prepared, and after treatment of various signals, radio-frequency currents that flowed through the heated object were determined as a two-dimensional current distribution profile by back-projection. A high correlation was observed between the distribution of radio-frequency currents detected with the coil antennas and the temperature distribution detected by thermography. Our method of the temperature distribution suggests the possibility of non-invasive evaluation of the temperature distribution in the target of hyperthermia and clinical usefulness of this method for temperature monitoring during hyperthermia

  5. Absolute and relative emission spectroscopy study of 3 cm wide planar radio frequency atmospheric pressure bio-plasma source

    Science.gov (United States)

    Deng, Xiaolong; Nikiforov, Anton Yu; Ionita, Eusebiu-Rosini; Dinescu, Gheorghe; Leys, Christophe

    2015-08-01

    The dynamics of low power atmospheric pressure radio frequency discharge generated in Ar gas in long gap of 3 cm is investigated. This plasma source is characterized and analyzed for possible large scale biomedical applications where low gas temperature and potential-less effluent are required. The discharge forms a homogenous glow-like afterglow in ambient air at input power of 30 W with low gas temperature of 330 K, which is desirable in biomedical applications. With absolute calibrated spectroscopy of the discharge, electron density of 0.4 × 1018 m-3 and electron temperature of 1.5 eV are obtained from continuum Bremsstrahlung radiation of the source. Time and spatial resolved emission spectroscopy is used to analyze discharge generation mechanism and active species formation. It is found that discharge dynamics strongly correlates with the discharge current waveform. Strong Ar(2p) excited states emission is observed nearby the electrodes surface on a distance up to 200 μm in the plasma sheath region at 10 ns after the current peak, whereas OH(A) emission is uniform along of the interelectrode gap.

  6. Radio Frequency Field Calculations for Plasma Heating Simulations in VASIMR

    Science.gov (United States)

    Ilin, A. V.; Díaz, F. R. Chang; Squire, J. P.; Carter, M. D.

    2002-01-01

    (VASIMR)1 is plasma heating by ion-cyclotron RF heating (ICRF). Mathematical simulation helps to design an ICRF antenna, i.e. make maximal absorption of RF power into the plasma in the resonance area. Another goal of a particle simulation is design of a magnetic nozzle and optimize the performance of VASIMR2. field in the plasma, 2) ion density and velocity, 3) ion-cyclotron radio-frequency electromagnetic field. The assumptions of quasineutral and collisionless plasma are based on the range of operating VASIMR parameters. Carlo simulations for systems of million of particles in a reasonable time and without the need for a powerful supercomputer. The particle to grid weighting method is used for calculating the ion density, which is used for recalculation of the electric potential and RF field. dimensional problem to a weighted sum over two-dimensional solutions. Absorption is introduced in the cold plasma model by adding an imaginary collision frequency to the RF driven frequency, which is equivalent to adding an imaginary particle mass in the dielectric tensor elements. static and RF fields using the VASIMR code2. The VASIMR and EMIR codes are then iterated to estimate the ICRF effects on the plasma density. The iteration is performed by calculating the RF fields with the EMIR code, and using these fields to follow nonlinear ion trajectories with the VASIMR code on the gyro-frequency time scale. The ion trajectories are used to generate RF power absorption values and a density input for the next EMIR calculation. The codes are iterated until the density profile becomes reasonably stable, then the collisional absorption parameter in the EMIR code is adjusted and the iteration is continued until the power deposited by the RF system matches the power absorbed by the ion trajectories in a global sense. electric field. The solved algebraic system of equations is represented by ill-conditioned 18-diagonal matrix with complex elements. Since early development of the

  7. Energy Saving Glass Lamination via Selective Radio Frequency Heating

    Energy Technology Data Exchange (ETDEWEB)

    Allan, Shawn M; Baranova, Inessa; Poley, Joseph; Reis, Henrique

    2012-02-27

    This project focused on advancing radio-frequency (RF) lamination technology closer to commercial implementation, in order to reduce the energy intensity of glass lamination by up to 90%. Lamination comprises a wide range of products including autoglass, architectural safety and innovative design glass, transparent armor (e.g. bullet proof glass), smart glass, mirrors, and encapsulation of photovoltaics. Lamination is also the fastest growing segment of glass manufacturing, with photovoltaics, architectural needs, and an anticipated transition to laminated side windows in vehicles. The state-of-the-art for glass lamination is to use autoclaves, which apply heat and uniform gas pressure to bond the laminates over the course of 1 to 18 hours. Laminates consist of layers of glass or other materials bonded with vinyl or urethane interlayers. In autoclaving, significant heat energy is lost heating the chamber, pressurized air, glass racks, and the glass. In RF lamination, the heat is generated directly in the vinyl interlayer, causing it to heat and melt quickly, in just 1 to 10 minutes, without significantly heating the glass or the equipment. The main purpose of this project was to provide evidence that low energy, rapid RF lamination quality met the same standards as conventionally autoclaved windows. The development of concepts for laminating curved glass with RF lamination was a major goal. Other primary goals included developing a stronger understanding of the lamination product markets described above, and to refine the potential benefits of commercial implementation. The scope of the project was to complete implementation concept studies in preparation for continuation into advanced development, pilot studies, and commercial implementation. The project consisted of 6 main tasks. The first dealt with lamination with poly-vinyl butyral (PVB) interlayers, which prior work had shown difficulties in achieving good quality laminates, working with Pilkington North

  8. Energy Saving Glass Lamination via Selective Radio Frequency Heating

    Energy Technology Data Exchange (ETDEWEB)

    Allan, Shawn M.

    2012-02-27

    This project focused on advancing radio-frequency (RF) lamination technology closer to commercial implementation, in order to reduce the energy intensity of glass lamination by up to 90%. Lamination comprises a wide range of products including autoglass, architectural safety and innovative design glass, transparent armor (e.g. bullet proof glass), smart glass, mirrors, and encapsulation of photovoltaics. Lamination is also the fastest growing segment of glass manufacturing, with photovoltaics, architectural needs, and an anticipated transition to laminated side windows in vehicles. The state-of-the-art for glass lamination is to use autoclaves, which apply heat and uniform gas pressure to bond the laminates over the course of 1 to 18 hours. Laminates consist of layers of glass or other materials bonded with vinyl or urethane interlayers. In autoclaving, significant heat energy is lost heating the chamber, pressurized air, glass racks, and the glass. In RF lamination, the heat is generated directly in the vinyl interlayer, causing it to heat and melt quickly, in just 1 to 10 minutes, without significantly heating the glass or the equipment. The main purpose of this project was to provide evidence that low energy, rapid RF lamination quality met the same standards as conventionally autoclaved windows. The development of concepts for laminating curved glass with RF lamination was a major goal. Other primary goals included developing a stronger understanding of the lamination product markets described above, and to refine the potential benefits of commercial implementation. The scope of the project was to complete implementation concept studies in preparation for continuation into advanced development, pilot studies, and commercial implementation. The project consisted of 6 main tasks. The first dealt with lamination with poly-vinyl butyral (PVB) interlayers, which prior work had shown difficulties in achieving good quality laminates, working with Pilkington North

  9. A Measurement Method of Time Jitter of a Laser Pulse with Respect to the Radio-Frequency Wave Phase in a Photocathode Radio-Frequency Gun

    Institute of Scientific and Technical Information of China (English)

    刘圣广; 李永贵; 王鸣凯

    2002-01-01

    In a photo-cathode radio-frequency (rf) gun, the micro-bunched charge output from the gun is dependent linearly on the laser injection phase, due to the Scottay effect in the process of photoemission and the procedure of the electron longitudinal acceleration. Based on this principle, a new method is proposed, which should be utilized to measure the time jitter between the driving laser pulse and the rf phase with a very high resolution of a few tens of femtoseconds.

  10. Understanding Pound-Drever-Hall locking using voltage controlled radio-frequency oscillators: An undergraduate experiment

    CERN Document Server

    Liekhus-Schmaltz, C E

    2011-01-01

    A senior undergraduate experiment has been developed for learning about frequency stabilization techniques using radio-frequency electronics. The primary objective is to frequency stabilize a voltage controlled oscillator to a cavity resonance at 800 MHz using the Pound-Drever-Hall scheme. This technique is commonly applied to stabilize lasers at optical frequencies, but by using radio-frequency equipment exclusively it is possible to systematically study various aspects of the technique more thoroughly, inexpensively, and free from eye hazards. Students also learn about modular radio-frequency electronics and basic feedback control loops. By varying the temperature of the resonator, the students may determine the thermal expansion coefficients of copper, aluminum, and super invar.

  11. Effect of Krypton Addition on Electron Cyclotron Resonance-Radio Frequency Hybrid Oxygen Plasma for Patterning Diamond Surfaces

    International Nuclear Information System (INIS)

    Electron cyclotron resonance radio frequency (ECR-rf) hybrid krypton-diluted oxygen plasmas were used to pattern the surfaces of diamond films with the assistance of a physical mask, while optical emission spectroscopy was employed to characterize the plasma. It was found that with krypton dilution the etching rate decreased, and also the aspect ratios of nanotips formed in micro-holes were significantly modified. The oxygen atomic densities were estimated by oxygen atom optical emission and argon actinometry. Under a microwave power of 300 W and rf bias of -300 V, the absolute density of ground-state oxygen atoms decreased from 1.3x1012 cm-3 to 1.4x1011 cm-3 as the krypton dilution ratio increased to 80%, accompanied by the decrease in the plasma excitation temperature. It is concluded that oxygen atoms play a dominant role in diamond etching. The relative variations in the horizontal and vertical etching rates induced by the addition of krypton are attributed to the observations of thicker nanotips at a high krypton dilution ratio.

  12. Microstructural characterization of radio frequency magnetron sputter-deposited Ga2O3:Mn phosphor thin films

    International Nuclear Information System (INIS)

    Ga2O3:Mn phosphor thin films have been prepared by radio frequency (rf) magnetron sputtering of a 2 mol % Mn-doped Ga2O3 target in an oxygen-argon mixture atmosphere. The deposition rate of the films decreased from 14 to 12 Aa/min when the working gas pressure decreased from 30 to 2 mTorr, while the O/Ga ratio of ∼1.5 did not systematically depend on the pressure. Films deposited at higher working gas pressure had a porous columnar structure containing a large void, typical of zone 1 growth, while films produced at lower pressure had relatively smooth surfaces with a dense structure, typical of zone T growth. The results obtained are consistent with energetic particle bombardment of the depositing films promoting surface adatom mobility at lower working gas pressure. Films deposited at working gas pressures≥15 mTorr showed a random orientation after a postdeposition anneal at 1000 deg. C. Below 15 mTorr, annealed films were strongly textured with the (111) and (020) planes parallel to the surface

  13. Elimination of transmissible spongiform encephalopathy infectivity and decontamination of surgical instruments by using radio-frequency gas-plasma treatment.

    Science.gov (United States)

    Baxter, H C; Campbell, G A; Whittaker, A G; Jones, A C; Aitken, A; Simpson, A H; Casey, M; Bountiff, L; Gibbard, L; Baxter, R L

    2005-08-01

    It has now been established that transmissible spongiform encephalopathy (TSE) infectivity, which is highly resistant to conventional methods of deactivation, can be transmitted iatrogenically by contaminated stainless steel. It is important that new methods are evaluated for effective removal of protein residues from surgical instruments. Here, radio-frequency (RF) gas-plasma treatment was investigated as a method of removing both the protein debris and TSE infectivity. Stainless-steel spheres contaminated with the 263K strain of scrapie and a variety of used surgical instruments, which had been cleaned by a hospital sterile-services department, were examined both before and after treatment by RF gas plasma, using scanning electron microscopy and energy-dispersive X-ray spectroscopic analysis. Transmission of scrapie from the contaminated spheres was examined in hamsters by the peripheral route of infection. RF gas-plasma treatment effectively removed residual organic residues on reprocessed surgical instruments and gross contamination both from orthopaedic blades and from the experimentally contaminated spheres. In vivo testing showed that RF gas-plasma treatment of scrapie-infected spheres eliminated transmission of infectivity. The infectivity of the TSE agent adsorbed on metal spheres could be removed effectively by gas-plasma cleaning with argon/oxygen mixtures. This treatment can effectively remove 'stubborn' residual contamination on surgical instruments. PMID:16033987

  14. P-type doping of hydrogenated amorphous silicon films with boron by reactive radio-frequency co-sputtering

    Science.gov (United States)

    Ohmura, Y.; Takahashi, M.; Suzuki, M.; Sakamoto, N.; Meguro, T.

    2001-12-01

    B has been successfully doped into the hydrogenated amorphous Si films without using explosive and/or toxic gases SiH 4 or B 2H 6 by reactive radio-frequency co-sputtering. The target used for co-sputtering was a composite target composed of a B-doped Si wafer and B chips attached on the Si wafer with silver powder bond. The maximum area fraction of B chips used was 0.11. Argon and hydrogen pressures were 5×10 -3 and 5×10 -4 Torr, respectively. Substrates were kept at 200°C or 250°C during sputtering. The maximum B concentration in the film obtained was 2×10 19 cm -3 from secondary ion mass spectroscopy measurement. Films with resistivity of 10 4-10 5 Ω cm were obtained, which was low for the above acceptor concentration, compared with other group III impurities doping, indicating the high doping efficiency of B. A heterostructure, which was prepared by co-sputtering these B-doped films on an n-type crystalline Si, shows a good rectification characteristic. A small photovoltaic effect is also observed.

  15. Theory study on a photonic-assisted radio frequency phase shifter with direct current voltage control

    International Nuclear Information System (INIS)

    A photonic-assisted radio frequency phase shifter with direct current voltage control is proposed using a polymer-based integrated Mach—Zehnder modulator. A closed-form expression of radio frequency (RF) signal power and phase is given. Theoretical calculation reveals that by carefully setting the bias voltages, RF signal power variation lower than 1-dB and phase accuracy less than 3° can be achieved and are not degraded by perturbation of modulation index once the bias voltage drift is kept within −3% ∼ 3%. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  16. The Murchison Widefield Array: The Square Kilometre Array Precursor at Low Radio Frequencies

    OpenAIRE

    Tingay, S. J.; Goeke, R.; Bowman, J.D.; Emrich, D.; Ord, S. M.; Mitchell, D. A.; Morales, M F; Booler, T.; Crosse, B.; Pallot, D.; Wicenec, A.; Arcus, W.; Barnes, D; Bernardi, G.; Briggs, F.

    2012-01-01

    The Murchison Widefield Array (MWA) is one of three Square Kilometre Array Precursor telescopes and is located at the Murchison Radio-astronomy Observatory in the Murchison Shire of the mid-west of Western Australia, a location chosen for its extremely low levels of radio frequency interference. The MWA operates at low radio frequencies, 80–300 MHz, with a processed bandwidth of 30.72 MHz for both linear polarisations, and consists of 128 aperture arrays (known as tiles) distributed over a ~3...

  17. Design of water-cooling system for 750 keV radio frequency quadrupole injector

    International Nuclear Information System (INIS)

    The cooling design of a 201.25 MHz, 750 keV radio frequency quadrupole injector is described in this paper. The essential parameters for the design of the cooling pipes are obtained from the RF structure design. The hydrodynamics and thermal characteristics are theoretically analyzed. Computer simulation is performed using the steady state thermal analysis module of the radio-frequency software. Numerical computation shows that the increase of temperature is controlled within 1 K, the accelerator can work steadily with this cooling system. The cooling design satisfies the physical requirement very well. (authors)

  18. An ultra sensitive radio frequency single electron transistor working up to 4.2 K

    OpenAIRE

    Brenning, Henrik; Kafanov, Sergey; Duty, Tim; Kubatkin, Sergey; Delsing, Per

    2006-01-01

    We present the fabrication and measurement of a radio frequency single electron transistor (rf-SET), that displays a very high charge sensitivity of 1.9 microlectrons/sqrt(Hz) at 4.2 K. At 40 mK, the charge sensitivity is 0.9 and 1.0 microlectrons/sqrt(Hz) in the superconducting and normal state respectively. The sensitivity was measured as a function of radio frequency amplitude at three different temperatures: 40 mK, 1.8 K and 4.2 K.

  19. Analysis of a discrete spectrum analyzer for the detection of radio frequency interference

    Science.gov (United States)

    Levitt, B. K.

    1977-01-01

    As the radio frequency spectrum becomes increasingly overcrowded, interference with mission-critical DSN operations is rising at an alarming rate. To alleviate this problem the DSN is developing a wideband surveillance system for on-site detection and identification of potential sources of radio frequency interference (RFI), which will complement the existing frequency coordination activities. The RFI monitoring system is based on a wideband, multi-look discrete spectrum analyzer operating on fast Fourier transform principles. An extensive general statistical analysis is presented of such spectrum analyzers and derives threshold detection performance formulas for signals of interest. These results are then applied to the design of the RFI spectrum analyzer under development.

  20. Effect of radio-frequency power levels on electron density in a confined two-frequency capacitively-coupled plasma processing tool

    International Nuclear Information System (INIS)

    The plasma electron density ne in a symmetric confined capacitive-coupled plasma processing tool containing Ar/O2/C4F8 gas mixtures is studied as a function of two, combined radio frequency (2 MHz+27 MHz) powers. For measuring ne we have used a floating hairpin resonance probe. The results show a linear increase in ne with 27 MHz power. Also the density is higher with an increase in 2 MHz power, in contrast with published particle-in-cell simulation results in argon where the plasma density decreased with increases in low frequency voltage, for fixed high frequency current [P. C. Boyle et al., J. Phys. D 37, 697 (2004)]. Analyzing the relative phase between radio frequency current and voltage, we observe slightly lower 2 MHz phase shifts at higher 2 MHz voltage, which is attributed to an increase in the real component of the current through the sheath. This is possible due to the increase in secondary electron emissions arising from ion bombardment, which is favored by an increase in 2 MHz voltage. We therefore conclude that the secondary electrons could play an important role in the discharge process

  1. Radio frequency sputter deposition of high-quality conductive and transparent ZnO:Al films on polymer substrates for thin film solar cells applications

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, S. [Departamento de Energias Renovables, Energia Solar Fotovoltaica, Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Avda. Complutense 22, 28040 Madrid (Spain)], E-mail: susanamaria.fernandez@ciemat.es; Martinez-Steele, A.; Gandia, J.J. [Departamento de Energias Renovables, Energia Solar Fotovoltaica, Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Avda. Complutense 22, 28040 Madrid (Spain); Naranjo, F.B. [Grupo de Ingenieria Fotonica (GRIFO), Departamento de Electronica, Escuela Politecnica Superior, Universidad de Alcala. Campus Universitario, 28871 Alcala de Henares, Madrid (Spain)

    2009-03-31

    Thick aluminum-doped zinc oxide films were deposited at substrate temperatures from 100 {sup o}C to room temperature on polyethylene terephthalate by radio frequency magnetron sputtering, varying the deposition parameters such as radio frequency power and working pressure. Structural, optical and electrical properties were analyzed using an x-ray diffractometer, a spectrophotometer and a four-point probe, respectively. Films were polycrystalline showing a strong preferred c-axis orientation (002). The best optical and electrical results were achieved using a substrate temperature of 100 {sup o}C. Furthermore, high transmittances close to 80% in the visible wavelength range were obtained for those films deposited at the lowest Argon pressure used of 0.2 Pa. In addition, resistivities as low as 1.1 x 10{sup -3} {omega} cm were reached deposited at a RF power of 75 W. Finally, a comparison of the properties of the films deposited on polymer and glass substrates was performed, obtaining values of the figure of merit for the films on polymer comparable to those obtained on glass substrates, 17,700 {omega}{sup -1} cm{sup -1} vs 14,900 {omega}{sup -1} cm{sup -1}, respectively.

  2. Combined effect of oxygen deficient point defects and Ni doping in radio frequency magnetron sputtering deposited ZnO thin films

    International Nuclear Information System (INIS)

    Ni doped ZnO thin films with oxygen deficiency have been synthesized on glass substrates by radio frequency magnetron sputtering technique using argon plasma. The combined effect of point defects generated due to oxygen vacancies and Ni doping on the optical and electrical properties of ZnO thin films has been studied in this work. Ni doping concentrations were varied and the structural, optical and electrical properties of the films were studied as a function of doping concentrations. The films were characterized with X-ray diffractometer, UV–Vis–NIR spectrophotometer, X-ray photoelectron spectroscopy, atomic force microscopy and electrical conductivity measurements. Oxygen deficient point defects (Schottky defects) made the ZnO thin film highly conducting while incorporation of Ni dopant made it more functional regarding their electrical and optical properties. The films were found to have tunable electrical conductivity with Ni doping concentrations. - Highlights: • ZnO thin films prepared by radio frequency magnetron sputtering technique • Synthesis process was stimulated to introduce Schottky-type point defects. • Point defects and external doping of Ni made ZnO thin films more functional. • Point defect induced high electrical conductivity in ZnO thin film. • Significant shift in optical bandgap observed in ZnO with Ni doping concentrations

  3. Combined effect of oxygen deficient point defects and Ni doping in radio frequency magnetron sputtering deposited ZnO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Saha, B., E-mail: biswajit.physics@gmail.com [Thin Film and Nano Science Laboratory, Department of Physics, Jadavpur University, 700 032 Kolkata (India); Department of Physics, National Institute of Technology Agartala, Jirania 799046, Tripura (India); Das, N.S.; Chattopadhyay, K.K. [Thin Film and Nano Science Laboratory, Department of Physics, Jadavpur University, 700 032 Kolkata (India)

    2014-07-01

    Ni doped ZnO thin films with oxygen deficiency have been synthesized on glass substrates by radio frequency magnetron sputtering technique using argon plasma. The combined effect of point defects generated due to oxygen vacancies and Ni doping on the optical and electrical properties of ZnO thin films has been studied in this work. Ni doping concentrations were varied and the structural, optical and electrical properties of the films were studied as a function of doping concentrations. The films were characterized with X-ray diffractometer, UV–Vis–NIR spectrophotometer, X-ray photoelectron spectroscopy, atomic force microscopy and electrical conductivity measurements. Oxygen deficient point defects (Schottky defects) made the ZnO thin film highly conducting while incorporation of Ni dopant made it more functional regarding their electrical and optical properties. The films were found to have tunable electrical conductivity with Ni doping concentrations. - Highlights: • ZnO thin films prepared by radio frequency magnetron sputtering technique • Synthesis process was stimulated to introduce Schottky-type point defects. • Point defects and external doping of Ni made ZnO thin films more functional. • Point defect induced high electrical conductivity in ZnO thin film. • Significant shift in optical bandgap observed in ZnO with Ni doping concentrations.

  4. Radio frequency sputter deposition of high-quality conductive and transparent ZnO:Al films on polymer substrates for thin film solar cells applications

    International Nuclear Information System (INIS)

    Thick aluminum-doped zinc oxide films were deposited at substrate temperatures from 100 oC to room temperature on polyethylene terephthalate by radio frequency magnetron sputtering, varying the deposition parameters such as radio frequency power and working pressure. Structural, optical and electrical properties were analyzed using an x-ray diffractometer, a spectrophotometer and a four-point probe, respectively. Films were polycrystalline showing a strong preferred c-axis orientation (002). The best optical and electrical results were achieved using a substrate temperature of 100 oC. Furthermore, high transmittances close to 80% in the visible wavelength range were obtained for those films deposited at the lowest Argon pressure used of 0.2 Pa. In addition, resistivities as low as 1.1 x 10-3 Ω cm were reached deposited at a RF power of 75 W. Finally, a comparison of the properties of the films deposited on polymer and glass substrates was performed, obtaining values of the figure of merit for the films on polymer comparable to those obtained on glass substrates, 17,700 Ω-1 cm-1 vs 14,900 Ω-1 cm-1, respectively

  5. Advances in radio frequency electric fields, ultraviolet light, and dense-phase carbon dioxide processing

    Science.gov (United States)

    In the quest to provide consumers with safe, nutritious, delicious, and affordable liquid foods, many nonthermal technologies have been researched. Radio frequency electric fields processing is related to pulsed electric fields processing and looks promising, yet has not been commercialized. Ultrav...

  6. Radio Frequency Electric Fields Inactivation of Escherichia coli in Apple Cider

    Science.gov (United States)

    Apple cider has been implicated in several outbreaks. Thermal pasteurization eliminates this threat, but it can detrimentally affect the quality of the cider. A nonthermal process using radio frequency electric fields (RFEF) was developed to pasteurize cider. An 80 kW RFEF pilot plant system was ...

  7. Radio Frequency Electric Fields Inactivation of Lactobacillus plantarum in Apple Cider

    Science.gov (United States)

    Radio frequency electric fields (RFEF) nonthermal processing has recently been shown to be effective at reducing Escherichia coli in fruit juices. While considerable effort and progress have been made in studying the effect of RFEF processing on this gram negative bacteria, there is a total lack of...

  8. Perancangan Sistem Pembayaran Biaya Parkir Secara Otomatis Menggunakan RFID (Radio Frequency Indentification)

    OpenAIRE

    Siahaan, Charles P M

    2014-01-01

    Proses pembayaran biaya parkir yang dilakukan dengan cara manual masih memiliki kelemahan. Permasalahan seperti kurang efisien dan kurang efektif merupakan contoh dari beberapa kelemahan yang ditimbulkan dari sistem parkir manual. Sistem perparkiran yang terstruktur dengan baik dan mampu menawarkan berbagai macam solusi dari permasalahan perparkiran yang ada merupakan sistem perparkiran yang sangat dibutuhkan saat ini. RFID (Radio Frequency Identification) bisa menjadi jawaban untuk memban...

  9. Electromagnetic interference from radio frequency identification inducing potentially hazardous incidents in critical care medical equipment

    NARCIS (Netherlands)

    Togt, R. van der; Lieshout, E.J. van; Hensbroek, R.; Beinat, E.; Binnekade, J.M.; Bakker, P.J.M.

    2008-01-01

    Context: Health care applications of autoidentification technologies, such as radio frequency identification (RFID), have been proposed to improve patient safety and also the tracking and tracing of medical equipment. However, electromagnetic interference (EMI) by RFID on medical devices has never b

  10. Radio frequency "sutureless" fistulotomy- a new way of treating fistula in anus

    Institute of Scientific and Technical Information of China (English)

    Pravin J.Gupta

    2003-01-01

    AIM: To explore the effect of the classical lay open technique or fistulotomy with the radio frequency surgical device in the treatment of fistula in anus.METHODS: In our study, the conventional 'lay open'technique, or 'fistulotomy' was performed by employing the radio frequency surgical device as an alternative to the traditional knife and scissors. In a span of 18 months starting from July 1999 to December 2000, 210 cases with fistula in anus of varied types were operated in our nursing home exclusively applying the radio frequency device.RESULTS: The results of the study were not only encouraging but also were satisfactory. A follow up of the operated patients with radio frequency surgery over a period of 15 months, i.e. from December 2000 to March 2002 was summarized as below: (a) average time taken by the patient to resume routine - 7 days; (b) none of the patient had any interference with the continence; (c) the wounds were found healed within an average time of 47 days; (d) delayed wound healing was noticed only in 7 patients; (e) recurrence/failure rate was reduced to as low as 1.5 percent.CONCLUSION: This technique has been found superior to the conventional fistulotomy in the sense that the time taken for the whole procedure is reduced to almost half, chances of bleeding are reduced to a minimum and the use of suture material is dispensed with. The procedure can safely be called a "Sutureless fistulotomy".

  11. Scheme to funnel ion beams with a radio-frequency quadrupole

    International Nuclear Information System (INIS)

    We describe a proposed method to funnel ion beams using a new form of the radio-frequency quadrupole (RFQ) structure. This RFQ accepts two bunched ion beams and combines them into a single final beam with interlaced microstructure pulses. It also provides uninterrupted periodic transverse focusing to facilitate the funneling of beams with high current and low emittance

  12. Dielectric properties of almond shells in the development of radio frequency and microwave pasteurization

    Science.gov (United States)

    To develop pasteurization treatments based on radio frequency (RF) or microwave energy, dielectric properties of almond shells were determined using an open-ended coaxial-probe with an impedance analyzer over a frequency range of 10 to 1800 MHz. Both the dielectric constant and loss factor of almond...

  13. Epiphysiodesis Made with Radio Frequency Ablation: First Results from a Pilot Study

    DEFF Research Database (Denmark)

    Shiguetomi Medina, Juan Manuel; Rahbek, Ole; Stødkilde-Jørgensen, Hans; Møller-Madsen, Bjarne

    the surrounding cartilage structures was found. The animals could walk normally after the anesthesia and no signs of pain or discomfort were presented during the follow-up period. Conclusions Epiphysiodesis using radio frequency ablation is an innovative technique that may represent an alternative way...

  14. The Diffusion and Impact of Radio Frequency Identification in Supply Chains: A Multi-Method Approach

    Science.gov (United States)

    Wu, Xiaoran

    2012-01-01

    As a promising and emerging technology for supply chain management, Radio Frequency Identification (RFID) is a new alternative to existing tracking technologies and also allows a range of internal control and supply chain coordination. RFID has generated a significant amount of interest and activities from both practitioners and researchers in…

  15. Investigation of Dual Radio-Frequency Driven Sheaths and Ion Energy Distributions Bombarding an Insulating Substrate

    Institute of Scientific and Technical Information of China (English)

    WANG Li-Hong; DAI Zhong-Ling; WANG Yu-Nian

    2006-01-01

    @@ Dual radio-frequency (rf) sources at widely different frequencies are often simultaneously used to separately optimize the plasma parameters and ion energy distributions (IEDs) incident onto a substrate. Characteristics of collisionless dual rf biased-sheaths and IEDs impinging on an insulating substrate are studied with a self consistent one-dimensional fluid model.

  16. Use of a radio-frequency resonance circuit in studies of alkali ionization in flames

    International Nuclear Information System (INIS)

    The construction of a radio-frequency resonance system and its use in the study of alkali metal ionization in flames is described. The author re-determines the values of the alkali ionization rate constants for a CO flame with N2 as diluent gas of known temperature using the RF resonance method. (Auth.)

  17. Radio frequency controlled synthetic wavelength sweep for absolute distance measurement by optical interferometry

    International Nuclear Information System (INIS)

    We present a new technique applied to the variable optical synthetic wavelength generation in optical interferometry. It consists of a chain of optical injection locking among three lasers: first a distributed-feedback laser is used as a master to injection lock an intensity-modulated laser that is directly modulated around 15 GHz by a radio frequency generator on a sideband. A second distributed-feedback laser is injection locked on another sideband of the intensity-modulated laser. The variable synthetic wavelength for absolute distance measurement is simply generated by sweeping the radio frequency over a range of several hundred megahertz, which corresponds to the locking range of the two slave lasers. In this condition, the uncertainty of the variable synthetic wavelength is equivalent to the radio frequency uncertainty. This latter has a relative accuracy of 10-7 or better, resulting in a resolution of ±25 μm for distances exceeding tens of meters. The radio frequency generator produces a linear frequency sweep of 1 ms duration (i.e., exactly equal to one absolute distance measurement acquisition time), with frequency steps of about 1 MHz. Finally, results of absolute distance measurements for ranges up to 10 m are presented

  18. Radio frequency controlled synthetic wavelength sweep for absolute distance measurement by optical interferometry.

    Science.gov (United States)

    Le Floch, Sébastien; Salvadé, Yves; Mitouassiwou, Rostand; Favre, Patrick

    2008-06-01

    We present a new technique applied to the variable optical synthetic wavelength generation in optical interferometry. It consists of a chain of optical injection locking among three lasers: first a distributed-feedback laser is used as a master to injection lock an intensity-modulated laser that is directly modulated around 15 GHz by a radio frequency generator on a sideband. A second distributed-feedback laser is injection locked on another sideband of the intensity-modulated laser. The variable synthetic wavelength for absolute distance measurement is simply generated by sweeping the radio frequency over a range of several hundred megahertz, which corresponds to the locking range of the two slave lasers. In this condition, the uncertainty of the variable synthetic wavelength is equivalent to the radio frequency uncertainty. This latter has a relative accuracy of 10(-7) or better, resulting in a resolution of +/-25 microm for distances exceeding tens of meters. The radio frequency generator produces a linear frequency sweep of 1 ms duration (i.e., exactly equal to one absolute distance measurement acquisition time), with frequency steps of about 1 MHz. Finally, results of absolute distance measurements for ranges up to 10 m are presented. PMID:18516123

  19. Determining radio frequency heating uniformity of mixed beans during disinfestation treatments

    Science.gov (United States)

    Since chickpeas and lentils are difficulty to artificially infest with live insects for radio frequency (RF) treatment validation, black-eyed peas and mung beans were selected to infest with insects before mixing with chickpeas and lentils. Temperature difference between black-eyed pea and chickpea ...

  20. Radio-frequency reflectometry on an undoped AlGaAs/GaAs single electron transistor

    DEFF Research Database (Denmark)

    MacLeod, S. J.; See, A. M.; Keane, Z. K.;

    2014-01-01

    Radio frequency reflectometry is demonstrated in a sub-micron undoped AlGaAs/GaAs device. Undoped single electron transistors (SETs) are attractive candidates to study single electron phenomena, due to their charge stability and robust electronic properties after thermal cycling. However, these...

  1. CoSMOS: Performance of Kurtosis Algorithm for Radio Frequency Interference Detection and Mitigation

    DEFF Research Database (Denmark)

    Misra, Sidharth; Kristensen, Steen Savstrup; Skou, Niels;

    2007-01-01

    The performance of a previously developed algorithm for Radio Frequency Interference (RFI) detection and mitigation is experimentally evaluated. Results obtained from CoSMOS, an airborne campaign using a fully polarimetric L-band radiometer are analyzed for this purpose. Data is collected using two...

  2. Radio frequency and microwave heating applicators and their use in industry

    Energy Technology Data Exchange (ETDEWEB)

    Metaxas, A.C. [Cambridge Univ. (United Kingdom)

    1995-12-01

    Radio frequency and microwave heating systems span the frequency range 10

  3. Application of Radio Frequency Identification (RFID) in Dairy Information Management

    Institute of Scientific and Technical Information of China (English)

    Wu Hong-da

    2012-01-01

    As a kind of brand-new technology, radio frequency identification management, data control and acquisition. This paper introduced food safety system construction, analyzed the advantages and problems in dairy modem suggestions for solution according to the practical situation. (RFID) plays an important role in dairy information tracing and culture function extension of managing breeding technology, and finally put forward some

  4. Industrial-scale radio frequency treatments for insect control in lentils

    Science.gov (United States)

    Radio frequency (RF) treatments are considered to be a potential postharvest technology for disinfesting legumes of internal seed pests such as the cowpea weevil. After treatment protocols are shown to control postharvest insects without significant quality degradation, it is important to scale-up l...

  5. Theoretical determination of plasma density in radio frequency discharges between dielectric-covered parallel plate electrodes

    International Nuclear Information System (INIS)

    Fundamental solutions for electromagnetic (EM) radio frequency (EM) discharges between parallel-plate electrodes were obtained theoretically using an electrostatic approximation, in particular, the produced plasma density and the minimum RF voltage for maintaining a plasma. The result shows that the RF discharges arise from a geometrical resonance of electron plasma wave. (Author)

  6. Optimization of ZnSe-SiO2 nanostructures deposited by radio-frequency magnetron sputtering: Correlations between plasma species and thin film composition, structural and microstructural properties

    International Nuclear Information System (INIS)

    ZnSe nanoparticle doped SiO2 films have been grown on various substrates at different deposition temperatures, radio-frequency power, Argon pressures and substrate to target distances, by means of reactive magnetron sputtering. A detailed study of the correlations between plasma species and thin film composition, structure and morphology is investigated using X-ray reflectivity and diffraction, Raman and optical emission spectroscopies and Rutherford backscattering technique. It is evidenced that the most sensitive species in the plasma is the Selenium and that the optimal deposition parameters correspond to random stress-free films with a high content of quasi-stoechiometric ZnSe cubic nanocrystallites. A few amount of ZnSe in the hexagonal structure is also evidenced in these films. Using proper deposition parameters, the SiO2/ZnSe proportion in the films and the mean ZnSe particles size around 3 nm are easily monitored

  7. A measurement method of time jitter of a laser pulse with respect to the radio-frequency wave phase in a photocathode radio-frequency gun

    International Nuclear Information System (INIS)

    In a photo-cathode radio-frequency (rf) gun, the micro-bunched charge output from the gun is dependent linearly on the laser injection phase, due to the Scottay effect in the process of photoemission and the procedure of the electron longitudinal acceleration. Based on this principle, a new method is proposed, which should be utilized to measure the time jitter between the driving laser pulse and the rf phase with a very high resolution of a few tens of femto-seconds

  8. Photocatalytic property of titanium dioxide thin films deposited by radio frequency magnetron sputtering in argon and water vapour plasma

    Science.gov (United States)

    Sirghi, L.; Hatanaka, Y.; Sakaguchi, K.

    2015-10-01

    The present work is investigating the photocatalytic activity of TiO2 thin films deposited by radiofrequency magnetron sputtering of a pure TiO2 target in Ar and Ar/H2O (pressure ratio 40/3) plasmas. Optical absorption, structure, surface morphology and chemical structure of the deposited films were comparatively studied. The films were amorphous and included a large amount of hydroxyl groups (about 5% of oxygen atoms were bounded to hydrogen) irrespective of the intentional content of water in the deposition chamber. Incorporation of hydroxyl groups in the film deposited in pure Ar plasma is explained as contamination of the working gas with water molecules desorbed by plasma from the deposition chamber walls. However, intentional input of water vapour into the discharge chamber decreased the deposition speed and roughness of the deposited films. The good photocatalytic activity of the deposited films could be attributed hydroxyl groups in their structures.

  9. Resonant-frequency discharge in a multi-cell radio frequency cavity

    International Nuclear Information System (INIS)

    We are reporting experimental results on a microwave discharge operating at resonant frequency in a multi-cell radio frequency (RF) accelerator cavity. Although the discharge operated at room temperature, the setup was constructed so that it could be used for plasma generation and processing in fully assembled active superconducting radio-frequency cryo-module. This discharge offers a mechanism for removal of a variety of contaminants, organic or oxide layers, and residual particulates from the interior surface of RF cavities through the interaction of plasma-generated radicals with the cavity walls. We describe resonant RF breakdown conditions and address the issues related to resonant detuning due to sustained multi-cell cavity plasma. We have determined breakdown conditions in the cavity, which was acting as a plasma vessel with distorted cylindrical geometry. We discuss the spectroscopic data taken during plasma removal of contaminants and use them to evaluate plasma parameters, characterize the process, and estimate the volatile contaminant product removal

  10. Remote Impedance-based Loose Bolt Inspection Using a Radio-Frequency Active Sensing Node

    International Nuclear Information System (INIS)

    This paper introduces an active sensing node using radio-frequency (RF) telemetry. This device has brought the traditional impedance-based structural health monitoring (SHM) technique to a new paradigm. The RF active sensing node consists of a miniaturized impedance measuring device (AD5933), a microcontroller (ATmega128L), and a radio frequency (RF) transmitter (XBee). A macro-fiber composite (MFC) patch interrogates a host structure by using a self-sensing technique of the miniaturized impedance measuring device. All the process including structural interrogation, data acquisition, signal processing, and damage diagnostic is being performed at the sensor location by the microcontroller. The RF transmitter is used to communicate the current status of the host structure. The feasibility of the proposed SHM strategy is verified through an experimental study inspecting loose bolts in a bolt-jointed aluminum structure

  11. The Murchison Widefield Array: the Square Kilometre Array Precursor at low radio frequencies

    CERN Document Server

    Tingay, S J; Bowman, J D; Emrich, D; Ord, S M; Mitchell, D A; Morales, M F; Booler, T; Crosse, B; Pallot, D; Wicenec, A; Arcus, W; Barnes, D; Bernardi, G; Briggs, F; Burns, S; Bunton, J D; Cappallo, R J; Colegate, T; Corey, B E; Deshpande, A; deSouza, L; Gaensler, B M; Greenhill, L J; Hall, J; Hazelton, B J; Herne, D; Hewitt, J N; Johnston-Hollitt, M; Kaplan, D L; Kasper, J C; Kincaid, B B; Koenig, R; Kratzenberg, E; Lonsdale, C J; Lynch, M J; McKinley, B; McWhirter, S R; Morgan, E; Oberoi, D; Pathikulangara, J; Prabu, T; Remillard, R A; Rogers, A E E; Roshi, A; Salah, J E; Sault, R J; Udaya-Shankar, N; Schlagenhaufer, F; Srivani, K S; Stevens, J; Subrahmanyan, R; Tremblay, S; Wayth, R B; Waterson, M; Webster, R L; Whitney, A R; Williams, A; Williams, C L; Wyithe, J S B

    2012-01-01

    The Murchison Widefield Array (MWA) is one of three Square Kilometre Array Precursor telescopes and is located at the Murchison Radio-astronomy Observatory in the Murchison Shire of the mid-west of Western Australia, a location chosen for its extremely low levels of radio frequency interference. The MWA operates at low radio frequencies, 80-300 MHz, with a processed bandwidth of 30.72 MHz for both linear polarisations, and consists of 128 aperture arrays (known as tiles) distributed over a ~3 km diameter area. Novel hybrid hardware/software correlation and a real-time imaging and calibration systems comprise the MWA signal processing backend. In this paper the as-built MWA is described both at a system and sub-system level, the expected performance of the array is presented, and the science goals of the instrument are summarised.

  12. A Review of the Radio Frequency Non-destructive Testing for Carbon-fibre Composites

    Directory of Open Access Journals (Sweden)

    Li Zhen

    2016-04-01

    Full Text Available The purpose of this paper is to review recent research on the applications of existing non-destructive testing (NDT techniques, especially radio frequency (RF NDT, for carbon-fibre reinforced plastics (CFRP composites. Electromagnetic properties of CFRP composites that are associated with RF NDT are discussed first. The anisotropic characteristic of the conductivity and the relationship between the penetration depth and conductivity should be paid much attention. Then, the well-established RF NDT including eddy current technique, microwave technique and RF-based thermography are well categorised into four types (i.e. electromagnetic induction, resonance, RF-based thermography and RF wave propagation and demonstrated in detail. The example of impact damage detection using the induction and resonance methods is given. Some discussions on the development (like industrial-scale automated scanning, three-dimensional imaging, short-range ultra-wideband (UWB imaging and the radio frequency identification technology (RFID-based NDT are presented.

  13. Optical frequency comb technology for ultra-broadband radio-frequency photonics

    CERN Document Server

    Torres-Company, Victor

    2014-01-01

    The outstanding phase-noise performance of optical frequency combs has led to a revolution in optical synthesis and metrology, covering a myriad of applications, from molecular spectroscopy to laser ranging and optical communications. However, the ideal characteristics of an optical frequency comb are application dependent. In this review, the different techniques for the generation and processing of high-repetition-rate (>10 GHz) optical frequency combs with technologies compatible with optical communication equipment are covered. Particular emphasis is put on the benefits and prospects of this technology in the general field of radio-frequency photonics, including applications in high-performance microwave photonic filtering, ultra-broadband coherent communications, and radio-frequency arbitrary waveform generation.

  14. Etching mechanism of niobium in coaxial Ar/Cl2 radio frequency plasma

    International Nuclear Information System (INIS)

    The understanding of the Ar/Cl2 plasma etching mechanism is crucial for the desired modification of inner surface of the three dimensional niobium (Nb) superconductive radio frequency cavities. Uniform mass removal in cylindrical shaped structures is a challenging task because the etch rate varies along the direction of gas flow. The study is performed in the asymmetric coaxial radio-frequency (rf) discharge with two identical Nb rings acting as a part of the outer electrode. The dependence of etch rate uniformity on pressure, rf power, dc bias, Cl2 concentration, diameter of the inner electrode, temperature of the outer cylinder, and position of the samples in the structure is determined. To understand the plasma etching mechanisms, we have studied several factors that have important influence on the etch rate and uniformity, which include the plasma sheath potential, Nb surface temperature, and the gas flow rate

  15. Etching mechanism of niobium in coaxial Ar/Cl{sub 2} radio frequency plasma

    Energy Technology Data Exchange (ETDEWEB)

    Upadhyay, J.; Im, Do; Popović, S.; Vušković, L. [Department of Physics, Center for Accelerator Science, Old Dominion University, Norfolk, Virginia 23529 (United States); Valente-Feliciano, A.-M.; Phillips, L. [Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States)

    2015-03-21

    The understanding of the Ar/Cl{sub 2} plasma etching mechanism is crucial for the desired modification of inner surface of the three dimensional niobium (Nb) superconductive radio frequency cavities. Uniform mass removal in cylindrical shaped structures is a challenging task because the etch rate varies along the direction of gas flow. The study is performed in the asymmetric coaxial radio-frequency (rf) discharge with two identical Nb rings acting as a part of the outer electrode. The dependence of etch rate uniformity on pressure, rf power, dc bias, Cl{sub 2} concentration, diameter of the inner electrode, temperature of the outer cylinder, and position of the samples in the structure is determined. To understand the plasma etching mechanisms, we have studied several factors that have important influence on the etch rate and uniformity, which include the plasma sheath potential, Nb surface temperature, and the gas flow rate.

  16. UTag: Long-range Ultra-wideband Passive Radio Frequency Tags

    Energy Technology Data Exchange (ETDEWEB)

    Dowla, F

    2007-03-14

    Long-range, ultra-wideband (UWB), passive radio frequency (RF) tags are key components in Radio Frequency IDentification (RFID) system that will revolutionize inventory control and tracking applications. Unlike conventional, battery-operated (active) RFID tags, LLNL's small UWB tags, called 'UTag', operate at long range (up to 20 meters) in harsh, cluttered environments. Because they are battery-less (that is, passive), they have practically infinite lifetimes without human intervention, and they are lower in cost to manufacture and maintain than active RFID tags. These robust, energy-efficient passive tags are remotely powered by UWB radio signals, which are much more difficult to detect, intercept, and jam than conventional narrowband frequencies. The features of long range, battery-less, and low cost give UTag significant advantage over other existing RFID tags.

  17. SVD-based Method for Radio Frequency Interference Suppression Applied to SAR

    Directory of Open Access Journals (Sweden)

    Yu Chunrui

    2012-03-01

    Full Text Available Synthetic aperture radar (SAR is a special type of active microwave sensor, which has got a wide range of applications in remote sensing. However, the performance of SAR systems may be affected by radio frequency interference (RFI in several geographic regions. A novel singular value decomposition method is proposed for radio frequency interference suppression applied to SAR. This method decomposes the singular vectors of the received signal with RFI into interference subspace and signal subspace. The orthogonality of the two subspaces is used to suppress the RFI. The point-target simulation is used to show the working principle of the proposed algorithm. The experimental results based on SAR real data are also shown to verify the proposed algorithm.Defence Science Journal, 2012, 62(2, pp.132-136, DOI:http://dx.doi.org/10.14429/dsj.62.1144

  18. Nanostructure evolution in cluster-assembled WOx films synthesized by radio-frequency assisted laser ablation

    International Nuclear Information System (INIS)

    We deposited WOx films by radio frequency assisted pulsed laser deposition (RF-PLD). We explored the roles of substrate temperature and ambient gas pressure-composition on film nanostructure to maximise the film surface area in view of gas sensing applications. A W target was ablated in highly reactive O2 at 5 Pa and 700 Pa, as well as in a mixed oxygen-helium atmosphere at 700 Pa. Corning glass was used as the substrate, at increasing temperatures. Process parameters such as laser fluence and wavelength, radio-frequency power, target to substrate distance were kept fixed. The influence of the deposition parameters on roughness, morphology, nanostructure, and bond coordination of the deposited films were studied by Atomic Force Microscopy, Scanning Electron Microscopy, Transmission Electron Microscopy, and micro-Raman spectroscopy. Nanoparticle formation, the development of an extended, open nanostructure and its evolution toward compact films are discussed. (orig.)

  19. Etching mechanism of niobium in coaxial Ar/Cl2 radio frequency plasma

    Energy Technology Data Exchange (ETDEWEB)

    Upadhyay, Janardan [Old Dominion Univ., Norfolk, VA (United States); Im, Do [Old Dominion Univ., Norfolk, VA (United States); Popovic, Svetozar [Old Dominion Univ., Norfolk, VA (United States); Valente-Feliciano, Anne -Marie [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Phillips, H. Larry [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Vuskovic, Leposova [Old Dominion Univ., Norfolk, VA (United States)

    2015-03-18

    The understanding of the Ar/Cl2 plasma etching mechanism is crucial for the desired modification of inner surface of the three dimensional niobium (Nb) superconductive radio frequency cavities. Uniform mass removal in cylindrical shaped structures is a challenging task because the etch rate varies along the direction of gas flow. The study is performed in the asymmetric coaxial radio-frequency (rf) discharge with two identical Nb rings acting as a part of the outer electrode. The dependence of etch rate uniformity on pressure, rf power, dc bias, Cl2 concentration, diameter of the inner electrode, temperature of the outer cylinder, and position of the samples in the structure is determined. Furthermore, to understand the plasma etching mechanisms, we have studied several factors that have important influence on the etch rate and uniformity, which include the plasma sheath potential, Nb surface temperature, and the gas flow rate.

  20. Radio frequency interference protection of communications between the Deep Space Network and deep space flight projects

    Science.gov (United States)

    Johnston, D. W. H.

    1981-01-01

    The increasing density of electrical and electronic circuits in Deep Space Station systems for computation, control, and numerous related functions has combined with the extension of system performance requirements calling for higher speed circuitry along with broader bandwidths. This has progressively increased the number of potential sources of radio frequency interference inside the stations. Also, the extension of spectrum usage both in power and frequency as well as the greater density of usage at all frequencies for national and international satellite communications, space research, Earth resource operations and defense, and particularly the huge expansion of airborne electronic warfare and electronic countermeasures operations in the Mojave area have greatly increased the potential number and severity of radio frequency interference incidents. The various facets of this problem and the efforts to eliminate or minimize the impact of interference on Deep Space Network support of deep space flight projects are described.

  1. INFLUENCE OF CONSTRUCTIVE AND TECHNOLOGICAL DEFECTS ON COAXIAL RADIO-FREQUENCY CABLE IMPEDANCE

    Directory of Open Access Journals (Sweden)

    G.V. Bezprozvannych

    2013-04-01

    Full Text Available Coaxial user's radio-frequency cables belong to a category of cable television network elements parameters of which essentially specify the system capabilities as a whole. The cable working frequency spectrum spreading to 1000 MHz along with digital television and soundtrack signals transmission and high-definition television introduction causes more rigid requirements for wave impedance and, consequently, for the cable design. The established norms on user's cable impedance deviations fail to answer the state-of-the-art requirements for granting a complex of interactive services. On the basis of calculations performed, values of internal and external conductor diameters deviations as well as dielectric permeability of the insulation material are validated. For up-to-date user's radio-frequency cables, the impedance deviation from the normalized average value of 75 Ohm should not exceed ± 2 Ohm.

  2. Time accuracy of a radio frequency identification patient tracking system for recording operating room timestamps.

    Science.gov (United States)

    Marjamaa, Riitta A; Torkki, Paulus M; Torkki, Markus I; Kirvelä, Olli A

    2006-04-01

    A patient tracking system is a promising tool for managing patient flow and improving efficiency in the operating room. Wireless location systems, using infrared or radio frequency transmitters, can automatically timestamp key events, thereby decreasing the need for manual data input. In this study, we measured the accuracy and precision of automatically documented timestamps compared with manual recording. Each patient scheduled for urgent surgery was given an active radio frequency/infrared transmitter. The prototype software tracked the patient throughout the perioperative process, automatically documenting the timestamps. Both automatic and traditional data entry were compared with the reference data. The absolute value of median error was 64% smaller (P Indoor Positioning System can help in managing patient flow and in increasing transparency with faster availability and better accuracy of data. PMID:16551921

  3. Characterization and properties of ZnO1-xSx alloy films fabricated by radio-frequency magnetron sputtering

    International Nuclear Information System (INIS)

    A series of ZnO1-xSx alloy films (0 ≤ x ≤ 1) were grown on quartz substrates by radio-frequency (rf) magnetron sputtering of ZnS ceramic target, using oxygen and argon as working gas. X-ray diffraction measurement shows that the ZnO1-xSx films have wurtzite structure with (0 0 2) preferential orientation in O-rich side (0 ≤ x ≤ 0.23) and zinc blende structure with (1 1 1) preferential orientation in S-rich side (0.77 ≤ x ≤ 1). However, when the S content is in the range of 0.23 1-xSx film consists of two phases of wurtzite and zinc blende or amorphous ZnO1-xSx phase. The band gap energy of the films shows non-linear dependence on the S content, with an optical bowing parameter of about 2.9 eV. The photoluminescence (PL) measurement reveals that the PL spectrum of the wurtzite ZnO1-xSx is dominated by visible band and its PL intensity and intensity ratio of UV to visible band decrease greatly compared with undoped ZnO. All as-grown ZnO1-xSx films behave insulating, but show n-type conductivity for w-ZnO1-xSx and maintain insulating properties for β-ZnO1-xSx after annealed. Mechanisms of effects of S on optical and electrical properties of the ZnO1-xSx alloy are discussed in the present work.

  4. Characteristics of anomalous skin effect and evolution of power absorption regions in a cylindrical radio frequency inductively coupled plasma

    International Nuclear Information System (INIS)

    In a low-pressure radio-frequency (13.56 MHz), inductively coupled argon plasma generated by a normal cylindrical rf coil, electric field, current density, and absorbed power density is calculated from magnetic field measured with a phase-resolved magnetic probe. The anomalous skin effect (ASE) for the cylindrical rf coil is compared to those previously reported for the planar and re-entrant cylindrical rf coils. Physical reasons for our observed characteristics of ASE are presented. With the increasing discharge power, the size and the number of negative and positive power absorption regions evolve into several distinct patterns. For the low discharge power (at 156.9 W), there is one area of positive and one area of negative power absorption in the radial direction. For the medium discharge power (279 W–683.5 W), there are two areas of negative and two areas of positive power absorption. For the even higher discharge power (above 803.5 W), the number of areas is the same as that of the medium discharge power, but the size of the inner positive and negative power absorption areas is approximately doubled and halved, respectively, while the outer positive and negative power absorption areas slightly shrinks. The evolution of positive and negative power absorption regions is explained as a result of electron thermal diffusion and the energy conversion between rf current and electric field. The spatial decays of electric field and current density are also elucidated by linking them with the positive and negative power absorption pattern

  5. Characteristics of anomalous skin effect and evolution of power absorption regions in a cylindrical radio frequency inductively coupled plasma

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Z. F., E-mail: zfding@dlut.edu.cn [Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams, Ministry of Education, School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116023 (China); Sun, B. [Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams, Ministry of Education, School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116023 (China); Xi' an Aerospace Propulsion Institute, China Aerospace Science and Technology Corporation, Xi' an 710100 (China); Huo, W. G. [Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams, Ministry of Education, School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116023 (China); School of Physics and Electronic Technology, Liaoning Normal University, Dalian 116029 (China)

    2015-06-15

    In a low-pressure radio-frequency (13.56 MHz), inductively coupled argon plasma generated by a normal cylindrical rf coil, electric field, current density, and absorbed power density is calculated from magnetic field measured with a phase-resolved magnetic probe. The anomalous skin effect (ASE) for the cylindrical rf coil is compared to those previously reported for the planar and re-entrant cylindrical rf coils. Physical reasons for our observed characteristics of ASE are presented. With the increasing discharge power, the size and the number of negative and positive power absorption regions evolve into several distinct patterns. For the low discharge power (at 156.9 W), there is one area of positive and one area of negative power absorption in the radial direction. For the medium discharge power (279 W–683.5 W), there are two areas of negative and two areas of positive power absorption. For the even higher discharge power (above 803.5 W), the number of areas is the same as that of the medium discharge power, but the size of the inner positive and negative power absorption areas is approximately doubled and halved, respectively, while the outer positive and negative power absorption areas slightly shrinks. The evolution of positive and negative power absorption regions is explained as a result of electron thermal diffusion and the energy conversion between rf current and electric field. The spatial decays of electric field and current density are also elucidated by linking them with the positive and negative power absorption pattern.

  6. Detecting a Hidden Radio Frequency Transmitter in Noise based on Amplitude using Swarm Intelligence

    OpenAIRE

    Nordmoen, Jørgen Halvorsen

    2014-01-01

    Radio Frequency transmitters are becoming ubiquitous. For instance people oftencarry around a mobile phone containing several such transmitters. Having theability to detect and locate such transmitters in noisy environments can there-fore be very beneficial in search and rescue and disaster management. By usingamplitude measurements, simple hardware can be deployed on small and cheapUnmanned Aerial Vehicles. The use of many cooperative Unmanned Aerial Vehi-cles should enable rapid search and ...

  7. Radio Frequency Nonionizing Radiation in a Community Exposed to Radio and Television Broadcasting

    OpenAIRE

    BURCH, JAMES B.; Clark, Maggie; Yost, Michael G.; Fitzpatrick, Cole T.E.; Bachand, Annette M.; Ramaprasad, Jaya; Reif, John S.

    2005-01-01

    Exposure to radio frequency (RF) nonionizing radiation from telecommunications is pervasive in modern society. Elevated disease risks have been observed in some populations exposed to radio and television transmissions, although findings are inconsistent. This study quantified RF exposures among 280 residents living near the broadcasting transmitters for Denver, Colorado. RF power densities outside and inside each residence were obtained, and a global positioning system (GPS) identified geogr...

  8. Radio Frequency Models of Novae in eruption. I. The Free-Free Process in Bipolar Morphologies

    OpenAIRE

    Ribeiro, V. A. R. M.; Chomiuk, L.; Munari, U.; Steffen, W.; Koning, N.; O'Brien, T. J.; Simon, T.; Woudt, P. A.; Bode, M. F.

    2014-01-01

    Observations of novae at radio frequencies provide us with a measure of the total ejected mass, density profile and kinetic energy of a nova eruption. The radio emission is typically well characterized by the free-free emission process. Most models to date have assumed spherical symmetry for the eruption, although it has been known for as long as there have been radio observations of these systems, that spherical eruptions are to simplistic a geometry. In this paper, we build bipolar models o...

  9. An Intelligent Traffic Flow Control System Based on Radio Frequency Identification and Wireless Sensor Networks

    OpenAIRE

    Kuei-Hsiang Chao; Pi-Yun Chen

    2014-01-01

    This study primarily focuses on the use of radio frequency identification (RFID) as a form of traffic flow detection, which transmits collected information related to traffic flow directly to a control system through an RS232 interface. At the same time, the sensor analyzes and judges the information using an extension algorithm designed to achieve the objective of controlling the flow of traffic. In addition, the traffic flow situation is also transmitted to a remote monitoring control syste...

  10. Challenges and opportunities of silent commerce - applying Radio Frequency Identification technology

    Directory of Open Access Journals (Sweden)

    Teuta Cata

    2006-04-01

    Full Text Available This research paper investigates applications of Radio Frequency Technology (RFID as an application of ubiquitous commerce. RFID has a wide application in the supply chain but still is very limited for customer support. This study introduces the concept of the Silent CRM (s-CRM which is an application of RFID to proactively support customer needs. Challenges of RFID application within companies, outside of companies and about the technology itself are discussed as well.

  11. Different modes of a capacitively coupled radio-frequency discharge in methane.

    Science.gov (United States)

    Schweigert, I V

    2004-04-16

    The transition between different regimes of a capacitevely coupled radio-frequency gas discharge in methane is studied with a combined particle-in-cell Monte Carlo collision algorithm over a wide range of gas pressure P and discharge current j. The results of this study are compared with known experimental and numerical results and summarized on a P-j phase diagram, which constitutes the areas of existence of different discharge regimes. PMID:15169290

  12. A Review of the Radio Frequency Non-destructive Testing for Carbon-fibre Composites

    OpenAIRE

    Li Zhen; Meng Zhaozong

    2016-01-01

    The purpose of this paper is to review recent research on the applications of existing non-destructive testing (NDT) techniques, especially radio frequency (RF) NDT, for carbon-fibre reinforced plastics (CFRP) composites. Electromagnetic properties of CFRP composites that are associated with RF NDT are discussed first. The anisotropic characteristic of the conductivity and the relationship between the penetration depth and conductivity should be paid much attention. Then, the well-established...

  13. Radio-frequency properties of stacked long Josephson junctions with nonuniform bias current distribution

    DEFF Research Database (Denmark)

    Filatrella, G; Pedersen, Niels Falsig

    1999-01-01

    We have numerically investigated the behavior of stacks of long Josephson junctions considering a nonuniform bias profile. In the presence of a microwave field the nonuniform bias, which favors the formation of fluxons, can give rise to a change of the sequence of radio-frequency induced steps. The...... amplitude of the steps is enhanced when the external frequency matches the fluxon shuttling regime. ©1999 American Institute of Physics....

  14. Successful Treatment of Canine Cutaneous Leishmaniasis Using Radio-Frequency Induced Heat (RFH) Therapy

    OpenAIRE

    Ahuja, Anil A.; Bumb, Ram A.; Rajesh D Mehta; Prasad, Neha; Tanwar, Ram K.; Satoskar, Abhay R.

    2012-01-01

    Canine cutaneous leishmaniasis (CCL) is a significant veterinary problem. Infected dogs also serve as parasite reservoirs and contribute to human transmission of cutaneous leishmaniasis (CL). Current treatments for CCL are cumbersome and toxic because they are prolonged and involve multiple injections of antimonials. Radio-frequency induced heat (RFH) therapy has been found to be highly effective against CL in humans. Here, we examined the efficacy of topical RFH therapy in the treatment of C...

  15. Impact of Radio-Frequency Identification (RFID) Technologies on the Hospital Supply Chain: A Literature Review

    OpenAIRE

    Coustasse, Alberto; Tomblin, Shane; Slack, Chelsea

    2013-01-01

    Supply costs account for more than one-third of the average operating budget and constitute the second largest expenditure in hospitals. As hospitals have sought to reduce these costs, radio-frequency identification (RFID) technology has emerged as a solution. This study reviews existing literature to gauge the recent and potential impact and direction of the implementation of RFID in the hospital supply chain to determine current benefits and barriers of adoption. Findings show that the appl...

  16. Occupational exposure to radio frequency/microwave radiation and the risk of brain tumors

    DEFF Research Database (Denmark)

    Berg, Gabriele; Spallek, Jacob; Schüz, Joachim;

    2006-01-01

    It is still under debate whether occupational exposure to radio frequency/microwave electromagnetic fields (RF/MW-EMF) contributes to the development of brain tumors. This analysis examined the role of occupational RF/MW-EMF exposure in the risk of glioma and meningioma. A population-based, case-.......81). However, the slight increase in risk observed with increasing duration of exposure merits further research with larger sample sizes....

  17. Adaptive Estimation of Line-of-sight Rate Measurement from a Radio Frequency Seeker

    Directory of Open Access Journals (Sweden)

    Anand M. Tapas

    2005-07-01

    Full Text Available The line-of-sight (LOS rate output from a radio frequency (RF seeker is widely used during the homing phase guidance of a tactical missile: The LOS rate is noisy and needs to be filtered.The application of an adaptive Kalman filter for the L.OS rate state estimation has been studied. This filter requires minimal a priori knowledge about technical parameters of the seeker. It isalso capable of estimating the variable noise statistics.

  18. Correction and Characterization of Radio Frequency Interference Signatures in L-band Synthetic Aperture Radar Data

    OpenAIRE

    Meyer, Franz; Nicoll, Jeremy; Doulgeris, Anthony Paul

    2013-01-01

    Radio frequency interference (RFI) is a known issue in low-frequency radar remote sensing. In synthetic aperture radar (SAR) image processing, RFI can cause severe degradation of image quality, distortion of polarimetric signatures, and an increase of the SAR phase noise level. To address this issue, a processing system was developed that is capable of reliably detecting, characterizing, and mitigating RFI signatures in SAR observations. In addition to being the basis for image correction, th...

  19. Radio Frequency Interference Detection and Mitigation Algorithms Based on Spectrogram Analysis

    Directory of Open Access Journals (Sweden)

    Jose Miguel Tarongi

    2011-10-01

    Full Text Available Radio Frequency Interference (RFI detection and mitigation algorithms based on a signal’s spectrogram (frequency and time domain representation are presented. The radiometric signal’s spectrogram is treated as an image, and therefore image processing techniques are applied to detect and mitigate RFI by two-dimensional filtering. A series of Monte-Carlo simulations have been performed to evaluate the performance of a simple thresholding algorithm and a modified two-dimensional Wiener filter.

  20. A new approach to mitigation of radio frequency interference in interferometric data

    OpenAIRE

    Athreya, Ramana

    2009-01-01

    Radio frequency interference (RFI) is the principal factor limiting the sensitivities of radio telescopes, particularly at frequencies below 1 GHz. I present a conceptually new approach to mitigation of RFI in interferometric data. This has been used to develop a software tool (RfiX) to remove RFI from observations using the Giant Metrewave Radio Telescope, India. However, the concept can be used to excise RFI in any interferometer. Briefly, the fringe-stopped correlator output of an interfer...

  1. Study of radio frequency interference effects on radiometry bands in urban environments

    OpenAIRE

    Forte Veliz, Giuseppe Francesco; Camps Carmona, Adriano José; Tarongí Bauzá, José Miguel; Vall-Llossera Ferran, Mercedes Magdalena

    2012-01-01

    Microwave radiometers are very accurate passive sensors that have been successfully used in Earth remote sensing during the last decades. Microwave radiometers measure thermal noise, therefore any other signal (radio-frequency interference or RFI) present in the band modifies the value of the measured power, and the corresponding estimated antenna temperature, from which the geophysical parameters will be retrieved. An on-going RFI survey shows how corrupted is the spectrum “protected” L-band...

  2. An introduction to factor analysis for radio frequency interference detection on satellite observations

    OpenAIRE

    Islam, Tanvir; Srivastava, Prashant K; Dai, Qiang; Gupta, Manika; Zhuo, Lu

    2015-01-01

    A novel radio frequency interference (RFI) detection method is introduced for satellite-borne passive microwave radiometer observations. This method is based on factor analysis, in which variability among observed and correlated variables is described in terms of factors. In the present study, this method is applied to the Tropical Rainfall Measuring Mission (TRMM)/TRMM Microwave Imager (TMI) and Aqua/Advanced Microwave Scanning Radiometer – Earth Observing System (AMSR-E) satellite measureme...

  3. CoSMOS: Performance of Kurtosis Algorithm for Radio Frequency Interference Detection and Mitigation

    OpenAIRE

    Misra, Sidharth; Kristensen, Steen Savstrup; Skou, Niels; Søbjærg, Sten Schmidl

    2007-01-01

    The performance of a previously developed algorithm for Radio Frequency Interference (RFI) detection and mitigation is experimentally evaluated. Results obtained from CoSMOS, an airborne campaign using a fully polarimetric L-band radiometer are analyzed for this purpose. Data is collected using two separate integration times, as a result of which sensitivity of the detection algorithm is measured. The impact of RFI on remotely sensed data over land and sea is also presented.

  4. Radio Frequency Interference Mitigation for Detection of Extended Sources with an Interferometer

    OpenAIRE

    Bower, Geoffrey C.

    2004-01-01

    Radio frequency interference (RFI) is a significant problem for current and future radio telescopes. We describe here a method for post-correlation cancellation of RFI for the special case of an extended source observed with an interferometer that spatially resolves the astronomical signal. In this circumstance, the astronomical signal is detected through the auto-correlations of each antenna but is not present in the cross-correlations between antennas. We assume that the RFI is detected in ...

  5. Radio Frequency Interference Detection and Mitigation Algorithms Based on Spectrogram Analysis

    OpenAIRE

    Jose Miguel Tarongi; Adriano Camps

    2011-01-01

    Radio Frequency Interference (RFI) detection and mitigation algorithms based on a signal’s spectrogram (frequency and time domain representation) are presented. The radiometric signal’s spectrogram is treated as an image, and therefore image processing techniques are applied to detect and mitigate RFI by two-dimensional filtering. A series of Monte-Carlo simulations have been performed to evaluate the performance of a simple thresholding algorithm and a modified two-dimensional Wiener filter....

  6. Contributions to radio frequency interference detection and mitigation in Earth observation

    OpenAIRE

    Forte Véliz, Giuseppe Francesco

    2014-01-01

    Radio Frequency Interference (RFI) is the most common problem for electronic measuring systems. The presence of those electromagnetic waves can harm the measurements taken from very sensitive instruments, like microwave radiometry or navigation systems. The accuracy and precision are compromised. A first step to mitigate those unwanted effects is to study the RFI properties. Different algorithms have been proposed to detect the interferences, but there is no method that works in all cases. ...

  7. Radio-Frequency Interference Detection and Mitigation Algorithms for Synthetic Aperture Radiometers

    OpenAIRE

    Antonio Gutierrez; Jose Barbosa; Rita Castro; Jose Miguel Tarongi; Mercedes Vall Llossera; Adriano Camps; Jerome Gourrion

    2011-01-01

    The European Space Agency (ESA) successfully launched the Soil Moisture and Ocean Salinity (SMOS) mission in November 2, 2009. SMOS uses a new type of instrument, a synthetic aperture radiometer named MIRAS that provides full-polarimetric multi-angular L-band brightness temperatures, from which regular and global maps of Sea Surface Salinity (SSS) and Soil Moisture (SM) are generated. Although SMOS operates in a restricted band (1400–1427 MHz), radio-frequency interference (RFI) appears in SM...

  8. Mechanical design of SXLS [Superconducting X-ray Lithography Source] radio-frequency cavity

    International Nuclear Information System (INIS)

    This paper presents the mechanical design of a Radio-Frequency (RF) cavity to be used on a compact storage ring for Superconducting X-ray Lithography Source (SXLS). Various design features of this cavity are discussed, including basic geometrical configuration, structural design, initial and operational tuning, vacuum multipactoring, power window, and damping of higher order modes. A second application of this cavity design for beam life extension in an existing storage ring is also described. 2 refs., 6 figs

  9. Growth Enhancement of Radish Sprouts Induced by Low Pressure O2 Radio Frequency Discharge Plasma Irradiation

    Science.gov (United States)

    Kitazaki, Satoshi; Koga, Kazunori; Shiratani, Masaharu; Hayashi, Nobuya

    2012-01-01

    We studied growth enhancement of radish sprouts (Raphanus sativus L.) induced by low pressure O2 radio frequency (RF) discharge plasma irradiation. The average length of radish sprouts cultivated for 7 days after O2 plasma irradiation is 30-60% greater than that without irradiation. O2 plasma irradiation does not affect seed germination. The experimental results reveal that oxygen related radicals strongly enhance growth, whereas ions and photons do not.

  10. Analysis of Radio Frequency Blackout for a Blunt-Body Capsule in Atmospheric Reentry Missions

    OpenAIRE

    Yusuke Takahashi; Reo Nakasato; Nobuyuki Oshima

    2016-01-01

    A numerical analysis of electromagnetic waves around the atmospheric reentry demonstrator (ARD) of the European Space Agency (ESA) in an atmospheric reentry mission was conducted. During the ARD mission, which involves a 70% scaled-down configuration capsule of the Apollo command module, radio frequency blackout and strong plasma attenuation of radio waves in communications with data relay satellites and air planes were observed. The electromagnetic interference was caused by highly dense pla...

  11. Two quantum oscillators coupled with a planar radio frequency ion trap

    Institute of Scientific and Technical Information of China (English)

    Chen Liang; Gao Ke-Lin

    2010-01-01

    In this scheme, two quantum oscillators in a planar radio frequency ion trap are coupled by the trap electrodes. The ions motional states encode the quantum bits (qubits), and a swap gate could be achieved. Under different conditions of the experiments, the intensity of the coupling betweentwo quantum oscillators and the dissipation of the system are calculated. We compute fidelities for a quantum swap gate and discuss experimental issues.

  12. INFLUENCE OF CONSTRUCTIVE AND TECHNOLOGICAL DEFECTS ON COAXIAL RADIO-FREQUENCY CABLE IMPEDANCE

    OpenAIRE

    G.V. Bezprozvannych; A.M. Boyko; O.G. Kessaev

    2013-01-01

    Coaxial user's radio-frequency cables belong to a category of cable television network elements parameters of which essentially specify the system capabilities as a whole. The cable working frequency spectrum spreading to 1000 MHz along with digital television and soundtrack signals transmission and high-definition television introduction causes more rigid requirements for wave impedance and, consequently, for the cable design. The established norms on user's cable impedance deviations fail t...

  13. Radio Frequency Numerical Simulation Techniques Based on Multirate Runge-Kutta Schemes

    OpenAIRE

    Oliveira, Jorge F.; Pedro, José C.

    2012-01-01

    Electronic circuit simulation, especially for radio frequency (RF) and microwave telecommunications, is being challenged by increasingly complex applications presenting signals of very different nature and evolving on widely separated time scales. In this paper, we will briefly review some recently developed ways to address these challenges, by describing some advanced numerical simulation techniques based on multirate Runge-Kutta schemes, which operate in the one-dimensional time and also wi...

  14. A radio frequency tracing experiment of bedload transport in a small braided mountain stream

    OpenAIRE

    F. Liébault; Chapuis, M.; H. Bellot; Deschâtres, M.

    2009-01-01

    / Radio frequency identification technology is used for monitoring the displacement of coarse particles in streams since the beginning of the 2000s. Passive integrated transponders (PIT tags) are small, cheap and long-lasting electronic tags that can be programmed with their own identification code. Initially used in environmental research for animal tracking, they have been deployed successfully in a variety of fluvial environments for coarse sediment tracing. Pioneering studies conducted in...

  15. Radio frequency regenerative oscillations in monolithic high-Q/V heterostructured photonic crystal cavities

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jinghui, E-mail: jy2484@columbia.edu, E-mail: tg2342@columbia.edu; Gu, Tingyi, E-mail: jy2484@columbia.edu, E-mail: tg2342@columbia.edu; Zheng, Jiangjun; Wei Wong, Chee [Optical Nanostructures Laboratory, Center for Integrated Science and Engineering, Solid-State Science and Engineering, and Mechanical Engineering, Columbia University, New York, New York 10027 (United States); Yu, Mingbin; Lo, Guo-Qiang; Kwong, Dim-Lee [The Institute of Microelectronics, 11 Science Park Road, Singapore Science Park II, Singapore, 117685 (Singapore)

    2014-02-10

    We report temporal and spectral domain observation of regenerative oscillation in monolithic silicon heterostructured photonic crystals cavities with high quality factor to mode volume ratios (Q/V). The results are interpreted by nonlinear coupled mode theory (CMT) tracking the dynamics of photon, free carrier population, and temperature variations. We experimentally demonstrate effective tuning of the radio frequency tones by laser-cavity detuning and laser power levels, confirmed by the CMT simulations with sensitive input parameters.

  16. Sum-rule analysis of radio-frequency spectroscopy of ultracold Fermi gas

    OpenAIRE

    Leggett, AJ; Zhang, S.

    2008-01-01

    We carried out an analysis based on sum rules and determined the radio-frequency spectroscopy shift observed in Chin 's experiment. It is shown that such a shift can be interpreted as spin correlations peculiar to a BCS-type state. An analytical form for the shift is obtained which enables us to make quantitative comparisons with the experiment throughout the crossover. We also calculated the width of the resonance. An interesting consequence is noticed, which can possibly be tested by future...

  17. Operational characteristics of a 100-mA, 2-MeV radio-frequency quadrupole

    International Nuclear Information System (INIS)

    A 100-mA, 2.07-MeV Radio-Frequency Quadrupole (RFQ III) has been commissioned and operated routinely on the Accelerator Test Stand (ATS) [1] at Los Alamos National Laboratory. To characterize the RFQ output beam dynamics, measurements were made of the beam transmission and of the transverse and longitudinal phase-space distributions. Data were taken for different RFQ III operating conditions and compared to simulations

  18. Sensitivity of a micromechanical displacement detector based on the radio-frequency single-electron transistor

    OpenAIRE

    Blencowe, Miles P.; Wybourne, Martin N.

    2000-01-01

    We investigate the tunneling shot noise limits on the sensitivity of a micromechanical displacement detector based on a metal junction, radio-frequency single-electron transistor (rf-SET). In contrast with the charge sensitivity of the rf-SET electrometer, the displacement sensitivity improves with increasing gate voltage bias and, with a suitably optimized rf-SET, displacement sensitivities of $10^{-6} {\\rm\\AA}/\\sqrt{\\rm Hz}$ may be possible.

  19. High performance superconducting radio frequency ingot niobium technology for continuous wave applications

    International Nuclear Information System (INIS)

    Future continuous wave (CW) accelerators require the superconducting radio frequency cavities with high quality factor and medium accelerating gradients (≤20 MV/m). Ingot niobium cavities with medium purity fulfill the specifications of both accelerating gradient and high quality factor with simple processing techniques and potential reduction in cost. This contribution reviews the current superconducting radiofrequency research and development and outlines the potential benefits of using ingot niobium technology for CW applications

  20. High performance superconducting radio frequency ingot niobium technology for continuous wave applications

    Energy Technology Data Exchange (ETDEWEB)

    Dhakal, Pashupati, E-mail: dhakal@jlab.org; Ciovati, Gianluigi, E-mail: gciovati@jlab.org; Myneni, Ganapati R., E-mail: rao@jlab.org [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Avenue, Newport News, VA 23606 (United States)

    2015-12-04

    Future continuous wave (CW) accelerators require the superconducting radio frequency cavities with high quality factor and medium accelerating gradients (≤20 MV/m). Ingot niobium cavities with medium purity fulfill the specifications of both accelerating gradient and high quality factor with simple processing techniques and potential reduction in cost. This contribution reviews the current superconducting radiofrequency research and development and outlines the potential benefits of using ingot niobium technology for CW applications.

  1. Radio frequency heating of foods: principles, applications and related properties--a review.

    Science.gov (United States)

    Piyasena, Punidadas; Dussault, Chantal; Koutchma, Tatiana; Ramaswamy, H S; Awuah, G B

    2003-01-01

    Radio frequency (RF) heating is a promising technology for food applications because of the associated rapid and uniform heat distribution, large penetration depth and lower energy consumption. Radio frequency heating has been successfully applied for drying, baking and thawing of frozen meat and in meat processing. However, its use in continuous pasteurization and sterilization of foods is rather limited. During RF heating, heat is generated within the product due to molecular friction resulting from oscillating molecules and ions caused by the applied alternating electric field. RF heating is influenced principally by the dielectric properties of the product when other conditions are kept constant. This review deals with the current status of RF heating applications in food processing, as well as product and system specific factors that influence the RF heating. It is evident that frequency level, temperature and properties of food, such as viscosity, water content and chemical composition affect the dielectric properties and thus the RF heating of foods. Therefore, these parameters should be taken into account when designing a radio frequency heating system for foods. PMID:14669879

  2. Trapping ions from a fast beam in a radio-frequency ion trap: Exploring the energy exchange with the longitudinal radio-frequency field

    DEFF Research Database (Denmark)

    Svendsen, Annette; Lammich, Lutz; Vad Andersen, John Erik;

    2013-01-01

    The possibility of injecting ions from an initially fast moving beam into a multipole radio-frequency (RF) ion trap without the use of buffer gas is described. The chosen trap geometry gives rise to an oscillating electric field along the direction of the incoming ions, and through an analytical...... kinetic energy even if their kinetic energy initially exceeds the depth of the trapping potential well. An experimental apparatus for trapping ions from a fast beam is described, and experimental investigations demonstrating the described trapping dynamics are presented....... model as well as numerical simulations it is demonstrated that the energy exchange between the injected ions and this oscillating field governs the trapping dynamics. Most notably, if ions arrive at the trap during specific phases of the RF field, they can be effectively decelerated and stored with low...

  3. An Analysis of Near Field and Application of a New Comb-shaped Antenna for Radio Frequency Identification

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new comb-shaped antenna for radio frequency identification is proposed. The kind of antenna can replace some antenna array. So it is very convenient for omnidirectional identification. The test result proves this antenna is viable.

  4. Radio Frequency over Glass Integrated into FTTx by using 1,3 um VCSELs: Experimental Performance Assessment

    DEFF Research Database (Denmark)

    Rodes Lopez, Roberto; Pham, Tien Thang; Jensen, Jesper Bevensee; Tafur Monroy, Idelfonso

    We experimental assess the performance of a 1,3 um VCSEL for Radio Frequency over Glass application supporting QPSK modulation up to 4 Gbps, over 26 km SSMF for application in future fiber-to-the-premise networks.......We experimental assess the performance of a 1,3 um VCSEL for Radio Frequency over Glass application supporting QPSK modulation up to 4 Gbps, over 26 km SSMF for application in future fiber-to-the-premise networks....

  5. Spatially resolved simulation of a radio-frequency driven micro-atmospheric pressure plasma jet and its effluent

    OpenAIRE

    Hemke, Torben; Wollny, Alexander; Gebhardt, Markus; Brinkmann, Ralf Peter; Mussenbrock, Thomas

    2011-01-01

    Radio frequency driven plasma jets are frequently employed as efficient plasma sources for surface modification and other processes at atmospheric pressure. The radio-frequency driven micro atmospheric pressure plasma jet ($\\mu$APPJ) is a particular variant of that concept whose geometry allows direct optical access. In this work, the characteristics of the $\\mu$APPJ operated with a helium-oxygen mixture and its interaction with a helium environment are studied by numerical simulation. The de...

  6. Absolute and relative emission spectroscopy study of 3 cm wide planar radio frequency atmospheric pressure bio-plasma source

    International Nuclear Information System (INIS)

    The dynamics of low power atmospheric pressure radio frequency discharge generated in Ar gas in long gap of 3 cm is investigated. This plasma source is characterized and analyzed for possible large scale biomedical applications where low gas temperature and potential-less effluent are required. The discharge forms a homogenous glow-like afterglow in ambient air at input power of 30 W with low gas temperature of 330 K, which is desirable in biomedical applications. With absolute calibrated spectroscopy of the discharge, electron density of 0.4 × 1018 m−3 and electron temperature of 1.5 eV are obtained from continuum Bremsstrahlung radiation of the source. Time and spatial resolved emission spectroscopy is used to analyze discharge generation mechanism and active species formation. It is found that discharge dynamics strongly correlates with the discharge current waveform. Strong Ar(2p) excited states emission is observed nearby the electrodes surface on a distance up to 200 μm in the plasma sheath region at 10 ns after the current peak, whereas OH(A) emission is uniform along of the interelectrode gap

  7. Solid state generator for powerful radio frequency ion sources in neutral beam injection systems

    International Nuclear Information System (INIS)

    Radio frequency ion sources used in neutral beam injection systems (NBI) of fusion machines are currently supplied by self-excited RF generators. These generators have both a low power efficiency and a limited frequency stability, therefore transistorized amplifiers are being considered for the power supply of the next generation of RF sources. A 75 kW generator, originally designed for broadcasting, has been tested with a negative ion source. High operational reliability and a very good matching to the plasma load has been demonstrated. These results make this generator type a very promising candidate for future NBI systems

  8. Diagnostics of silane and germane radio frequency plasmas by coherent anti-Stokes Raman spectroscopy

    Science.gov (United States)

    Perry, Joseph W.; Shing, Y. H.; Allevato, C. E.

    1988-01-01

    In situ plasma diagnostics using coherent anti-Stokes Raman spectroscopy have shown different dissociation characteristics for GeH4 and SiH4 in radio frequency (rf) plasma-enhanced chemical vapor deposition of amorphous silicon germanium alloy (a-SiGe:H) thin films. The GeH4 dissociation rate in rf plasmas is a factor of about 3 larger than that of SiH4. Plasma diagnostics have revealed that the hydrogen dilution of the SiH4 and GeH4 mixed plasma plays a critical role in suppressing the gas phase polymerization and enhancing the GeH4 dissociation.

  9. Breakdown in hydrogen and deuterium gases in static and radio-frequency fields

    International Nuclear Information System (INIS)

    We report the results of a combined experimental and modeling study of the electrical breakdown of hydrogen and deuterium in static (DC) and radio-frequency (RF) (13.56 MHz) electric fields. For the simulations of the breakdown events, simplified models are used and only electrons are traced by Monte Carlo simulation. The experimental DC Paschen curve of hydrogen is used for the determination of the effective secondary electron emission coefficient. A very good agreement between the experimental and the calculated RF breakdown characteristics for hydrogen is found. For deuterium, on the other hand, presently available cross section sets do not allow a reproduction of RF breakdown characteristics

  10. Incorporation of radio frequency identification tag in dentures to facilitate recognition and forensic human identification.

    OpenAIRE

    Nuzzolese, E; Marcario, V; Di Vella, G

    2010-01-01

    Forensic identification using odontology is based on the comparison of ante-mortem and post mortem dental records. The insertion of a radio frequency identification (RFId) tag into dentures could be used as an aid to identify decomposed bodies, by storing personal identification data in a small transponder that can be radio-transmitted to a reader connected to a computer. A small passive, 12 x 2,1 mm, read-only RFId-tag was incorporated into the manufacture of three trial complete upper dentu...

  11. Gold Nanoparticle-Based Sensors Activated by External Radio Frequency Fields

    DEFF Research Database (Denmark)

    Della Vedova, Paolo; Ilieva, Mirolyuba; Zhurbenko, Vitaliy;

    2015-01-01

    A novel molecular beacon (a nanomachine) is constructed that can be actuated by a radio frequency (RF) field. The nanomachine consists of the following elements arranged in molecular beacon configuration: a gold nanoparticle that acts both as quencher for fluorescence and a localized heat source......; one reporter fluorochrome, and; a piece of DNA as a hinge and recognition sequence. When the nanomachines are irradiated with a 3 GHz RF field the fluorescence signal increases due to melting of the stem of the molecular beacon. A control experiment, performed using molecular beacons synthesized...

  12. Verification of nonlinear particle simulation of radio frequency waves in tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Kuley, A., E-mail: akuley@uci.edu; Lin, Z. [Department of Physics and Astronomy, University of California Irvine, California 92697 (United States); Bao, J. [Department of Physics and Astronomy, University of California Irvine, California 92697 (United States); Fusion Simulation Center, Peking University, Beijing 100871 (China); Wei, X. S.; Xiao, Y. [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Zhang, W. [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Sun, G. Y. [Department of Physics, Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen 361005 (China); Fisch, N. J. [Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08540 (United States); Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2015-10-15

    Nonlinear simulation model for radio frequency waves in fusion plasmas has been developed and verified using fully kinetic ion and drift kinetic electron. Ion cyclotron motion in the toroidal geometry is implemented using Boris push in the Boozer coordinates. Linear dispersion relation and nonlinear particle trapping are verified for the lower hybrid wave and ion Bernstein wave (IBW). Parametric decay instability is observed where a large amplitude pump wave decays into an IBW sideband and an ion cyclotron quasimode (ICQM). The ICQM induces an ion perpendicular heating, with a heating rate proportional to the pump wave intensity.

  13. The design of a radio frequency quadrupole LINAC for the RIB project at VECC Kolkata

    Indian Academy of Sciences (India)

    V Banerjee; Alok Chakrabarti; Arup Bandyopadhyay; T K Bhaumik; M Mondal; T K Chakraborty; H Pande; O Kamigaito; A Goto; Y Yano

    2002-12-01

    A radio frequency quadrupole LINAC has been designed for the VECC-RIB project for an input beam energy of 1.0 keV/u and / ≥ 1/16. The output energy will be about 90 keV/u for a 3.4 m long, 35 MHz structure. A half-scale cold model of the RFQ has been fabricated and tested for rf structure design study. The beam dynamics and rf-structure design along with the results of the cold model tests will be presented.

  14. Electrical and thermal analyses for the radio-frequency circuit of ITER NBI ion source

    Energy Technology Data Exchange (ETDEWEB)

    Zamengo, A. [Consorzio RFX, EURATOM-ENEA Association, Corso Stati Uniti, 4, 35127 Padova (Italy)], E-mail: andrea.zamengo@igi.cnr.it; Recchia, M. [Consorzio RFX, EURATOM-ENEA Association, Corso Stati Uniti, 4, 35127 Padova (Italy); Department of Electrical Engineering, University of Padua, Via Gradenigo 6/A, 35131 Padova (Italy); Kraus, W. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany); Bigi, M. [Consorzio RFX, EURATOM-ENEA Association, Corso Stati Uniti, 4, 35127 Padova (Italy); Martens, C. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany); Toigo, V. [Consorzio RFX, EURATOM-ENEA Association, Corso Stati Uniti, 4, 35127 Padova (Italy)

    2009-06-15

    This paper covers specific electrical and thermal aspects of the radio-frequency (RF) circuit which supplies the ion source of the International Thermonuclear Experimental Reactor (ITER) Neutral Beam Injector (NBI). Firstly, a matching circuit for the RF Antennas is presented and a possible solution for the matching components discussed, in relation to the anticipated equivalent circuit parameters of the RF driven plasma. Secondly, the thermal behaviour of the RF transmission line is analyzed, utilising finite element tools, to evaluate the RF line overtemperature under the heaviest foreseen operating conditions.

  15. Hydrogen production by radio frequency plasma stimulation in methane hydrate at atmospheric pressure

    OpenAIRE

    Putra, Andi Erwin Eka

    2013-01-01

    Methane hydrate, formed by injecting methane into 100 g of shaved ice at a pressure of 7 MPa and reactor temperature of 0 ??C, was decomposed by applying 27.12 MHz radio frequency plasma in order to produce hydrogen. The process involved the stimulation of plasma in the methane hydrate with a variable input power at atmospheric pressure. It was observed that production of CH4 is optimal at a slow rate of CH4 release from the methane hydrate, as analyzed by in light of the steam...

  16. Tuning the work function of graphene by nitrogen plasma treatment with different radio-frequency powers

    International Nuclear Information System (INIS)

    Graphene prepared by the chemical vapor deposition method was treated with nitrogen plasma under different radio-frequency (rf) power conditions in order to experimentally study the change in the work function. Control of the rf power could change the work function of graphene from 4.91 eV to 4.37 eV. It is shown that the increased rf power may lead to the increased number of graphitic nitrogen, increasing the electron concentration, and shifting the Fermi level to higher energy. The ability to controllably tune the work function of graphene is essential for optimizing the efficiency of optoelectronic and electronic devices.

  17. Radio frequency effect on the sheath capacitance in a low density plasma

    International Nuclear Information System (INIS)

    In this work we describe the use of the nonlinear properties of the sheath capacitance in a low density plasma to produce parametric amplification of RF signals in a high frequency band (H.F.). The experiment has been carried out in the Linear Mirror Device LISA of the Universidade Federal Fluminense, where a helium plasma was produced using a radio-frequency source built at UFF, with variable (10 watts to 100 watts) and frequency of 28 MHz. The experimental results shows good agreement between the theoretical model of sheat capacitance. This allows one to predict, within a limited range, the sheath capacitance variation as a function of certain plasma parameters. (author)

  18. Radio frequency induction plasma generator 80-kV test stand operation

    International Nuclear Information System (INIS)

    Beam extraction tests at energies up to 80 kV were performed using a radio frequency induction (RFI) plasma generator hydrogen ion source. A 7 x 10-cm2, long pulse accelerator was operated with a 10 x 10-cm2 axial magnetic cusp bucket and a magnetic-filter bucket. Atomic fractions (up to 85% H+), plasma production efficiencies (roughly-equal0.6 A of beam per kW rf power), and beam divergence were at least as good as with arc plasmas in similar chambers. Potential advantages of the RFI plasma sources for large-scale applications are ease of operation, reliability, and extended service life

  19. Lattice Wave of Magnetized Spherical Dust in Radio-Frequency Sheath with Negative Ions

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Lattice wave of magnetized spherical dust in radio-frequency sheath with negative ions is investigated. The dispersion relation of two-dimensional hexagonal lattice horizontal wave and the influence of negative ions and magnetic field intensity on the wave are also investigated. The results show that for two-dimensional hexagonal horizontal lattice wave, negative ions reduce the wave frequency at the range of long-wavelength, whereas raising the wave frequency at the range of short-wavelength and magnetic held contributes to dropping the wave frequency a little.

  20. Improvement on control system of the JT-60 radio frequency heating system

    Energy Technology Data Exchange (ETDEWEB)

    Shinozaki, Shin-ichi; Moriyama, Shinichi; Hiranai, Shinichi [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Sato, Fumiaki [Nippon Advanced Technology Co., Ltd., Tokai, Ibaraki (Japan)

    2003-03-01

    On the JT-60 radio frequency (RF) heating system, the decrease in the activity ratio was a problem because of the deterioration of the control system. To improve the reliability, we replaced CAMAC system for a power injection control system, which was a main cause of the trouble, with the microprocessor system. And, a function of computer supported programming function of RF power injection form was introduced, which contributed to reduce a load of operators. Furthermore, personal computers with network communication were introduced to improve a maintenance ability of the control system. As a result, the activity ratio of the RF heating system was improved significantly. (author)

  1. Gamma-Ray Bursts Subset and Supernova Remnants Low Radio-Frequency Turnover

    Institute of Scientific and Technical Information of China (English)

    LIU Xiang

    2000-01-01

    Durations of gamma-ray bursts (GRB's) are featured by >2s subset and <2s one, with initial corresponding energy ratio being 20:1. It is found that supernova remants(SNR 's) turnover frequencies peak at 100 and 500 MHz. After assuming that GRB's originate from hypernova and making an analysis on the evolution of GRB's, we find that the initial energy of two GRB subsets leads to a different radio-frequency turnover of their remnant spectra, which accords positively with the turnover-frequency ratio of SNR's.

  2. Experimental observation and computational analysis of striations in electronegative capacitively coupled radio-frequency plasmas

    CERN Document Server

    Liu, Yong-Xin; Korolov, Ihor; Donko, Zoltan; Wang, You-Nian; Schulze, Julian

    2016-01-01

    Self-organized spatial structures in the light emission from the ion-ion capacitive RF plasma of a strongly electronegative gas (CF4) are observed experimentally for the first time. Their formation is analyzed and understood based on particle-based kinetic simulations. These "striations" are found to be generated by the resonance between the driving radio-frequency and the eigenfrequency of the ion-ion plasma (derived from an analytical model) that establishes a modulation of the electric field, the ion densities, as well as the energy gain and loss processes of electrons in the plasma. The growth of the instability is followed by the numerical simulations.

  3. Separation Process of Polydisperse Particles in the Plasma of Radio-frequency Discharge

    Directory of Open Access Journals (Sweden)

    D.G. Batryshev

    2014-07-01

    Full Text Available Method of separation of polydisperse particles in the plasma of radio-frequency (RF discharge is considered. Investigation of plasma equipotential field gave conditions for separation. The purpose of this work was an obtaining of monodisperse particles in the plasma of RF discharge. Samples of monodisperse microparticles of silica and alumina were obtained. The size and chemical composition of samples were studied on a scanning electron microscope Quanta 3D 200i (SEM, USA FEI company. Average size of separated silica nanoparticles is 600 nm, silica and alumina microparticles is 5 mkm.

  4. Deposition of transparent, conductive tin oxide films on glass using a radio-frequency induction heater.

    Science.gov (United States)

    Solano, I; Schwoebel, P R

    2009-12-01

    Tin oxide films are often used as transparent, conductive coatings on glass in the scientific research setting. The standard approach of depositing these films in an oven leads to poor visibility of the substrate and thus inhibits the ready formation of uniform, low resistivity films. In this note we describe a simple tin oxide film deposition technique using a radio-frequency induction heater that allows for in situ visualization of the deposition process and resulting film. Uniform films having resistivities as low as 2 mohm cm with transmittances of approximately 85% in the visible light spectrum were readily deposited. PMID:20059179

  5. Solid state generator for powerful radio frequency ion sources in neutral beam injection systems

    Energy Technology Data Exchange (ETDEWEB)

    Kraus, W.; Fantz, U.; Heinemann, B.; Franzen, P.

    2015-02-15

    Radio frequency ion sources used in neutral beam injection systems (NBI) of fusion machines are currently supplied by self-excited RF generators. These generators have both a low power efficiency and a limited frequency stability, therefore transistorized amplifiers are being considered for the power supply of the next generation of RF sources. A 75 kW generator, originally designed for broadcasting, has been tested with a negative ion source. High operational reliability and a very good matching to the plasma load has been demonstrated. These results make this generator type a very promising candidate for future NBI systems.

  6. [Determination of electron density in atmospheric pressure radio frequency dielectric barrier discharges by Stark broadening].

    Science.gov (United States)

    Li, Sen; Liu, Zhong-wei; Chen, Qiang; Liu, Fu-ping; Wang, Zheng-duo; Yang, Li-zhen

    2012-01-01

    The use of high frequency power to generate plasma at atmospheric pressure is a relatively new development. An apparatus of atmospheric pressure radio frequency dielectric barrier discharge was constructed. Plasma emission based measurement of electron density in discharge columns from Stark broadening Ar is discribed. The spacial profile of electron density was studied. In the middle of the discharge column, as the input power increases from 138 to 248 W, the electron density rises from 4.038 x 10(21) m(-3) to 4.75 x 10(21) m(-3). PMID:22497121

  7. A novel radio frequency coil for veterinary magnetic resonance imaging system

    International Nuclear Information System (INIS)

    In this article, a novel designed radio frequency (RF) coil is designed and built for the imaging of puppies in a V-shape permanent magnetic resonance imaging (MRI) system. Two sets of Helmholtz coil pairs with a V-shape structure are used to improve the holding of an animal in the coil. The homogeneity and the sensitivity of the RF field in the coil are analysed by theoretical calculation. The size and the shape of the new coil are optimized and validated by simulation through using the finite element method (FEM). Good magnetic resonance (MR) images are achieved on a shepherd dog. (condensed matter: structure, thermal and mechanical properties)

  8. NASA Standard Initiator Susceptibility to UHF and S-Band Radio Frequency Power and Lightning Strikes

    Science.gov (United States)

    Burnham, Karen; Scully, Robert; Norgard, John

    2013-01-01

    The NASA Standard Initiator (NSI) is an important piece of pyrotechnic equipment used in many space applications. This presentation will outline the results of a series of tests done at UHF and S-Band frequencies to determine NSI susceptibility to Radio Frequency (RF) power. The results show significant susceptibility to pulsed RF power in the S-Band region. Additional testing with lightning pulses injected into the firing line harness, modelling the indirect effects of a lightning strike to a spacecraft, showed no vulnerability

  9. Breakdown in hydrogen and deuterium gases in static and radio-frequency fields

    CERN Document Server

    Korolov, I

    2015-01-01

    We report the results of a combined experimental and modeling study of the electrical breakdown of hydrogen and deuterium in static (DC) and radio-frequency (RF, 13.56 MHz) electric fields. For the simulations of the breakdown events, simplified models are used and only electrons are traced by Monte Carlo simulation. The experimental DC Paschen curve of hydrogen is used for the determination of the effective secondary electron emission coefficient. A very good agreement between the experimental and the calculated RF breakdown characteristics for hydrogen is found. For deuterium, on the other hand, presently available cross section sets do not allow a reproduction of RF breakdown characteristics.

  10. High resolution kilometric range optical telemetry in air by radio frequency phase measurement

    Science.gov (United States)

    Guillory, Joffray; Šmíd, Radek; García-Márquez, Jorge; Truong, Daniel; Alexandre, Christophe; Wallerand, Jean-Pierre

    2016-07-01

    We have developed an optical Absolute Distance Meter (ADM) based on the measurement of the phase accumulated by a Radio Frequency wave during its propagation in the air by a laser beam. In this article, the ADM principle will be described and the main results will be presented. In particular, we will emphasize how the choice of an appropriate photodetector can significantly improve the telemeter performances by minimizing the amplitude to phase conversion. Our prototype, tested in the field, has proven its efficiency with a resolution better than 15 μm for a measurement time of 10 ms and distances up to 1.2 km.

  11. Radio frequency interference noise reduction using a field programmable gate array for SQUID applications

    International Nuclear Information System (INIS)

    It is important to remove large environmental noise in superconducting quantum interference device (SQUID) measurement without magnetic shielding. Active noise control (ANC) is one of the effective methods to reduce environmental noise. Recently, SQUIDs have been used in various applications at high frequencies, such as nuclear quadrupole resonance (NQR). The NQR frequency from explosives is in the range 0.5-5 MHz. In this case, an NQR sensor is exposed to AM radio frequency interference (RFI). The feasibility of the ANC system for RFI that used digital signal processing was studied. Our investigation showed that this digital ANC system can be applied to SQUID measurements for RFI suppression

  12. Radio Frequency Interference Mitigation for the Planned SMAP Radar and Radiometer

    Science.gov (United States)

    Spencer, Michael; Chan, Samuel; Belz, Eric; Piepmeier, Jeffrey; Mohammed, Priscilla; Kim, Edward; Johnson, Joel T.

    2011-01-01

    NASA's planned SMAP mission will utilize a radar operating in a band centered on 1.26 GHz and a co-observing radiometer operating at 1.41 GHz to measure surface soil moisture. Both the radar and radiometer sub-systems are susceptible to radio frequency interference (RFI). Any significant impact of such interference requires mitigation in order to avoid degradation in the SMAP science products. Studies of RFT detection and mitigation methods for both the radar and radiometer are continuing in order to assess the risk to mission products and to refine the performance achieved.

  13. An analytical solution for the electrical properties of a Radio Frequency Quadrupole (RFQ) with simple vanes

    Science.gov (United States)

    Lancaster, H.

    1982-02-01

    Although the SUPERFISH program is used for calculating the design parameters of an radio frequency quadrupole (RFQ) structure with complex vanes, an analytical solution for electrical properties of an RFQ with simple vanes provides insight into the parametric behavior of these more complicated resonators. The fields in an inclined plane wave guide with proper boundary conditions match those in one quadrant of an RFQ. The principle of duality is used to exploit the solutions to a radial transmission line in solving the field equations. Calculated are the frequency equation, frequency sensitivity factors (5), electric field (E), magnetic field (H), stored energy (U), power dissipation (P), and quality factor (Q).

  14. Verification of nonlinear particle simulation of radio frequency waves in tokamak

    International Nuclear Information System (INIS)

    Nonlinear simulation model for radio frequency waves in fusion plasmas has been developed and verified using fully kinetic ion and drift kinetic electron. Ion cyclotron motion in the toroidal geometry is implemented using Boris push in the Boozer coordinates. Linear dispersion relation and nonlinear particle trapping are verified for the lower hybrid wave and ion Bernstein wave (IBW). Parametric decay instability is observed where a large amplitude pump wave decays into an IBW sideband and an ion cyclotron quasimode (ICQM). The ICQM induces an ion perpendicular heating, with a heating rate proportional to the pump wave intensity

  15. Beam characterization of a new continuous wave radio frequency quadrupole accelerator

    International Nuclear Information System (INIS)

    A new Continuous Wave (CW) Radio Frequency Quadrupole (RFQ) for the ATLAS (Argonne Tandem Linac Accelerator System) Intensity Upgrade was developed, built and tested at Argonne National Laboratory. We present here a characterization of the RFQ output beam in the longitudinal phase space, as well as a measurement of the transverse beam halo. Measurement results are compared to simulations performed using the beam dynamics code TRACK. -- Highlights: • Beam commissioning of a new CW RFQ has been performed at Argonne National Laboratory. • Energy spread and bunch shape measurements were conducted. • The formation of a beam halo in the transverse phase space was studied

  16. Transmission of Moessbauer rays through ferromagnets in radio-frequency magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Dzyublik, A. Ya., E-mail: dzyublik@ukr.net [Institute for Nuclear Research (Ukraine); Sadykov, E. K. [Kazan (Volga region) Federal University (Russian Federation); Petrov, G. I. [Kazan State Power Engineering University (Russian Federation); Arinin, V. V.; Vagizov, F. G. [Kazan (Volga region) Federal University (Russian Federation); Spivak, V. Yu. [Institute for Nuclear Research (Ukraine)

    2013-08-15

    The transmission of Moessbauer radiation through a thick ferromagnetic crystal, exposed to a radio-frequency (rf) magnetic field, is studied. The quantum-mechanical dynamical scattering theory is developed, taking into account the periodical reversals of the magnetic field at the nuclei. The Moessbauer forward scattering (FS) spectra of the weak ferromagnet FeBO{sub 3} placed into rf field are measured. It is found that the coherent gamma wave in the crystal absorbs or emits only couples of the rf photons. As a result, the FS spectra consist of equidistant lines spaced by twice the frequency of the rf field in contrast to the absorption spectra.

  17. Moessbauer absorption by thick ferromagnets in radio-frequency magnetic field

    CERN Document Server

    Dzyublik, A Y

    2002-01-01

    The dynamical scattering theory is developed for transmission of the Moessbauer radiation through a ferromagnetic absorber of arbitrary thickness whose magnetization periodically reverses under the influence of an external radio-frequency (RF) magnetic field. The thickness dependence of the Moessbauer absorption spectrum as well as the time dependence and energy distribution of the transmitted beam are analyzed. The transmitted spectrum as a function of the frequency of transmitted gamma-quanta, reveals a sideband structure separated by twice the frequency of the RF field, which collapses to a single line at high frequencies.

  18. Review of low-noise radio-frequency amplifiers based on superconducting quantum interference device

    International Nuclear Information System (INIS)

    Superconducting quantum interference device (SQUID) is a sensitive detector of magnetic flux signals. Up to now, the main application of SQUIDs has been measurements of magnetic flux signals in the frequency range from near DC to several MHz. Recently, cryogenic low-noise radio-frequency (RF) amplifiers based on DC SQUID are under development aiming to detect RF signals with sensitivity approaching quantum limit. In this paper, we review the recent progress of cryogenic low-noise RF amplifiers based on SQUID technology.

  19. A Bar Code and Radio-Frequency Identification System for Transfusion Safety

    Institute of Scientific and Technical Information of China (English)

    Sandler SG; DiBandi L; Langeberg A; Gibble J; Wilson C; Feldman CF

    2006-01-01

    This presentation will describe a pilot study of radio-frequency (RF) identification tags ("chips") that was conducted in parallel with standard procedures for the collection and testing of Red Blood Cells (Greater Chesapeake and Potomac Region, American Red Cross Biomedical Services, Baltimore, MD) and transfusion (Georgetown University Hospital, Washington, DC). The purpose of the study was to evaluate whether multi-write RF chips could be attached to blood bags, programmed, and used to facilitate the collection of information from (1) a blood bag manufacturer to (2) a blood collection center and, subsequently, to (3) a hospital transfusion service.

  20. Collision-induced radio-frequency transitions in CH 3I

    Science.gov (United States)

    Tamassia, F.; Danieli, R.; Scappini, F.

    1999-02-01

    The highly sensitive method of radio-frequency-infrared double resonance inside a CO 2 laser is applied to study collision-induced transitions in CH 3I in a four-level double resonance scheme. Pure nuclear quadrupole resonances are observed as the result of collision population transfer between different rotational levels. The intensity ratios of the collision-induced dips to the corresponding three-level double resonance signals are measured for a number of transitions in the ground and excited vibrational states. Collision selection rules in the pure gas and in mixtures with polar and non-polar gases are discussed.

  1. Radio Frequency Mapping using an Autonomous Robot: Application to the 2.4 GHz Band

    Science.gov (United States)

    Lebreton, J. M.; Murad, N. M.; Lorion, R.

    2016-03-01

    Radio signal strength measurement systems are essential to build a Radio Frequency (RF) mapping in indoor and outdoor environments for different application scenarios. This paper presents an autonomous robot making the construction of a radio signal mapping, by collecting and forwarding different useful information related to all access point devices and inherent to the robot towards the base station. A real case scenario is considered by measuring the RF field from our department network. The RF signal mapping consistency is shown by fitting the measurements with the radio signal strength model in two-dimensional area, and a path-loss exponent of 2.3 is estimated for the open corridor environment.

  2. Development and operation of the twin radio frequency single electron transistor for solid state qubit readout

    OpenAIRE

    Buehler, T. M.; Reilly, D. J.; Starrett, R. P.; Court, N. A.; Hamilton, A. R.; Dzurak, A.S.; Clark, R.G.

    2003-01-01

    Ultra-sensitive detectors and readout devices based on the radio frequency single electron transistor (rf-SET) combine near quantum-limited sensitivity with fast operation. Here we describe a twin rf-SET detector that uses two superconducting rf-SETs to perform fast, real-time cross-correlated measurements in order to distinguish sub-electron signals from charge noise on microsecond time-scales. The twin rf-SET makes use of two tuned resonance circuits to simultaneously and independently addr...

  3. Superconducting radio frequency technology: Expanding the horizons of physics and technology

    International Nuclear Information System (INIS)

    This paper describes a major new technology supporting the further evolution of accelerators: superconducting radio frequency (SRF) technology, which is today on the verge of large-scale application in accelerators. Originally foreseen in the early 1960s as a promising technology, SRF only recently has overcome several technological and practical hurdles. SRF accelerating structures promise low rf losses and high gradients under cw operation. High-quality, intense cw beams can be accelerated without risk of melting the structure and without requiring enormous amounts of input rf power

  4. Indication of radio frequency interference (RFI) sources for solar burst monitoring in Malaysia

    Science.gov (United States)

    Hamidi, Z. S.; Abidin, Z. Z.; Ibrahim, Z. A.; Shariff, N. N. M.

    2012-06-01

    Apart of monitoring the Sun project, the Radio Frequency Interference (RFI) surveying in the region of (1-1200) MHz has been conducted. The main objective of this surveying is to test and qualify the potential of monitoring a continuous radio emission of Solar in Malaysia. This work is also an initiative of International Space Weather Initiative (ISWI) project where Malaysia is one of the country that participate a e-Callisto Spectrometer network in order to study the behavior of Solar radio burst in frequency of (45-800) MHz region which will be install in this October. Detail results will indicate the potential of monitoring a solar in Malaysia.

  5. Application of Inductively Coupled Wireless Radio Frequency Probe to Knee Joint in Magnetic Resonance Image

    Directory of Open Access Journals (Sweden)

    Yuki Katayama

    2009-10-01

    Full Text Available An inductively coupled wireless coil for a radio frequency (RF probe has been designed and applied to a human knee joint to improve the signal to noise ratio (SNR in a magnetic resonance image (MRI. A birdcage type of a primary coil and a Helmholtz type of a wireless secondary coil have been manufactured. The coils were applied to a human knee with a 3 T MRI system. SNR was calculated both in the proton density image and in the T2 weighted image of MRI. The experimental results show that the designed coils are effective to increase SNR in the human knee MRI.

  6. Superconducting radio-frequency resonator in magnetic fields up to 6 T

    Science.gov (United States)

    Ebrahimi, M. S.; Stallkamp, N.; Quint, W.; Wiesel, M.; Vogel, M.; Martin, A.; Birkl, G.

    2016-07-01

    We have measured the characteristics of a superconducting radio-frequency resonator in an external magnetic field. The magnetic field strength has been varied with 10 mT resolution between zero and 6 T. The resonance frequency and the quality factor of the resonator have been found to change significantly as a function of the magnetic field strength. Both parameters show a hysteresis effect which is more pronounced for the resonance frequency. Quantitative knowledge of such behaviour is particularly important when experiments require specific values of resonance frequency and quality factor or when the magnetic field is changed while the resonator is in the superconducting state.

  7. A novel radio frequency coil for veterinary magnetic resonance imaging system

    Science.gov (United States)

    Meng, Bin; Huang, Kai-Wen; Wang, Wei-Min

    2010-07-01

    In this article, a novel designed radio frequency (RF) coil is designed and built for the imaging of puppies in a V-shape permanent magnetic resonance imaging (MRI) system. Two sets of Helmholtz coil pairs with a V-shape structure are used to improve the holding of an animal in the coil. The homogeneity and the sensitivity of the RF field in the coil are analysed by theoretical calculation. The size and the shape of the new coil are optimized and validated by simulation through using the finite element method (FEM). Good magnetic resonance (MR) images are achieved on a shepherd dog.

  8. Transmission of Mössbauer rays through ferromagnets in radio-frequency magnetic field

    International Nuclear Information System (INIS)

    The transmission of Mössbauer radiation through a thick ferromagnetic crystal, exposed to a radio-frequency (rf) magnetic field, is studied. The quantum-mechanical dynamical scattering theory is developed, taking into account the periodical reversals of the magnetic field at the nuclei. The Mössbauer forward scattering (FS) spectra of the weak ferromagnet FeBO3 placed into rf field are measured. It is found that the coherent gamma wave in the crystal absorbs or emits only couples of the rf photons. As a result, the FS spectra consist of equidistant lines spaced by twice the frequency of the rf field in contrast to the absorption spectra

  9. Analysis of Higher Order Modes in Large Superconducting Radio Frequency Accelerating Structures

    CERN Document Server

    Galek, Tomasz; Brackebusch, Korinna; Van Rienen, Ursula

    2015-01-01

    Superconducting radio frequency cavities used for accelerating charged particle beams are commonly used in accelerator facilities around the world. The design and optimization of modern superconducting RF cavities requires intensive numerical simulations. Vast number of operational parameters must be calculated to ensure appropriate functioning of the accelerating structures. In this study, we primarily focus on estimation and behavior of higher order modes in superconducting RF cavities connected in chains. To calculate large RF models the state-space concatenation scheme, an efficient hybrid method, is employed.

  10. DC normal glow discharges in atmospheric pressure atomic and molecular gases

    International Nuclear Information System (INIS)

    DC glow discharges were experimentally investigated in atmospheric pressure helium, argon, hydrogen, nitrogen and air. The discharges were characterized by visualization of the discharges and voltage and current measurements for current of up to several milliamperes. Significant differences are seen in the gas temperature; however all the discharges appear to operate as temperature and pressure scaled versions of low pressure discharges. In the normal glow discharges, features such as negative glow, Faraday dark space and positive column regions are clearly observable. In hydrogen and to a lesser degree in helium and argon standing striations of the positive column were visible in the normal glow regime. Normal glow characteristics such as normal current density at the cathode and constant electric field in the positive column are observed although there are some unexplained effects. The emission spectra for each of the discharges were studied. Also the rotational and vibrational temperature of the discharges were measured by adding trace amounts of N2 to the discharge gas and comparing modeled optical emission spectra of the N2 2nd positive system with spectroscopic measurements from the discharge. The gas temperatures for a 3.5 mA normal glow discharge were around 420 K, 680 K, 750 K, 890 K and 1320 K in helium, argon, hydrogen, nitrogen and air, respectively. Measured vibrational and excitation temperatures indicate non-thermal discharge operation. Mixtures of gases achieved intermediate temperatures.

  11. Radio frequency reflectometry and charge sensing of a precision placed donor in silicon

    International Nuclear Information System (INIS)

    We compare charge transitions on a deterministic single P donor in silicon using radio frequency reflectometry measurements with a tunnel coupled reservoir and DC charge sensing using a capacitively coupled single electron transistor (SET). By measuring the conductance through the SET and comparing this with the phase shift of the reflected radio frequency (RF) excitation from the reservoir, we can discriminate between charge transfer within the SET channel and tunneling between the donor and reservoir. The RF measurement allows observation of donor electron transitions at every charge degeneracy point in contrast to the SET conductance signal where charge transitions are only observed at triple points. The tunnel coupled reservoir has the advantage of a large effective lever arm (∼35%), allowing us to independently extract a neutral donor charging energy ∼62 ± 17 meV. These results demonstrate that we can replace three terminal transistors by a single terminal dispersive reservoir, promising for high bandwidth scalable donor control and readout

  12. An unshielded radio-frequency atomic magnetometer with sub-femtoTesla sensitivity

    International Nuclear Information System (INIS)

    We demonstrate a radio-frequency potassium-vapor magnetometer operating with sensitivities of 0.3 fT/√(Hz) at 0.5 MHz and 0.9 fT/√(Hz) at 1.31 MHz in the absence of radio-frequency and mu-metal or magnetic shielding. The use of spatially separated magnetometers, two voxels within the same cell, permits for the subtraction of common mode noise and the retention of a gradient signal, as from a local source. At 0.5 MHz the common mode noise was white and measured to be 3.4 fT/√(Hz); upon subtraction the noise returned to the values observed when the magnetometer was shielded. At 1.31 MHz, the common mode noise was from a nearby radio station and was reduced by a factor of 33 upon subtraction, limited only by the radio signal picked up by receiver electronics. Potential applications include in-the-field low-field magnetic resonance, such as the use of nuclear quadrupole resonance for the detection of explosives

  13. Analysis of Radio Frequency Blackout for a Blunt-Body Capsule in Atmospheric Reentry Missions

    Directory of Open Access Journals (Sweden)

    Yusuke Takahashi

    2016-01-01

    Full Text Available A numerical analysis of electromagnetic waves around the atmospheric reentry demonstrator (ARD of the European Space Agency (ESA in an atmospheric reentry mission was conducted. During the ARD mission, which involves a 70% scaled-down configuration capsule of the Apollo command module, radio frequency blackout and strong plasma attenuation of radio waves in communications with data relay satellites and air planes were observed. The electromagnetic interference was caused by highly dense plasma derived from a strong shock wave generated in front of the capsule because of orbital speed during reentry. In this study, the physical properties of the plasma flow in the shock layer and wake region of the ESA ARD were obtained using a computational fluid dynamics technique. Then, electromagnetic waves were expressed using a frequency-dependent finite-difference time-domain method using the plasma properties. The analysis model was validated based on experimental flight data. A comparison of the measured and predicted results showed good agreement. The distribution of charged particles around the ESA ARD and the complicated behavior of electromagnetic waves, with attenuation and reflection, are clarified in detail. It is suggested that the analysis model could be an effective tool for investigating radio frequency blackout and plasma attenuation in radio wave communication.

  14. High-energy sources at low radio frequency: the Murchison Widefield Array view of Fermi blazars

    CERN Document Server

    Giroletti, M; D'Abrusco, R; Lico, R; Burlon, D; Hurley-Walker, N; Johnston-Hollitt, M; Morgan, J; Pavlidou, V; Bell, M; Bernardi, G; Bhat, R; Bowman, J D; Briggs, F; Cappallo, R J; Corey, B E; Deshpande, A A; Ewall-Rice, A; Emrich, D; Gaensler, B M; Goeke, R; Greenhill, L J; Hazelton, B J; Hindson, L; Kaplan, D L; Kasper, J C; Kratzenberg, E; Feng, L; Jacobs, D; Kurdryavtseva, N; Lenc, E; Lonsdale, C J; Lynch, M J; McKinley, B; McWhirter, S R; Mitchell, D A; Morales, M F; Morgan, E; Oberoi, D; Offringa, A R; Ord, S M; Pindor, B; Prabu, T; Procopio, P; Riding, J; Rogers, A E E; Roshi, A; Shankar, N Udaya; Srivani, K S; Subrahmanyan, R; Tingay, S J; Waterson, M; Wayth, R B; Webster, R L; Whitney, A R; Williams, A; Williams, C L

    2016-01-01

    Low-frequency radio arrays are opening a new window for the study of the sky, both to study new phenomena and to better characterize known source classes. Being flat-spectrum sources, blazars are so far poorly studied at low radio frequencies. We characterize the spectral properties of the blazar population at low radio frequency compare the radio and high-energy properties of the gamma-ray blazar population, and search for radio counterparts of unidentified gamma-ray sources. We cross-correlated the 6,100 deg^2 Murchison Widefield Array Commissioning Survey catalogue with the Roma blazar catalogue, the third catalogue of active galactic nuclei detected by Fermi-LAT, and the unidentified members of the entire third catalogue of gamma-ray sources detected by \\fermilat. When available, we also added high-frequency radio data from the Australia Telescope 20 GHz catalogue. We find low-frequency counterparts for 186 out of 517 (36%) blazars, 79 out of 174 (45%) gamma-ray blazars, and 8 out of 73 (11%) gamma-ray bl...

  15. Radio-Frequency Heating of Sloshing Ions in a Straight Field Line Mirror

    International Nuclear Information System (INIS)

    Sloshing ions, the energetic ions with a velocity distribution concentrated to a certain pitch angle, play an important role in plasma confinement in mirrors. They are normally produced in mirror traps with neutral beam injection. They also could be generated by ion-cyclotron heating. In the present report two radio-frequency heating scenarios to sustain a sloshing ion population in a newly proposed mirror device, the straight field line mirror, are examined. The first one consists in the ion cyclotron heating in two-ion species plasma using longitudinal wave conversion a fundamental harmonic heating of deuterium ions in tritium plasma. This scheme provides efficient ion heating for high deuterium ''minority'' concentration without substantial power deposition to the electrons. The second scenario is based on the second harmonic of deuterium ions. The study uses numerical 3D calculations for the time-harmonic boundary problem for Maxwell's equations. For the radio-frequency heating in both schemes, simple strap antenna is used. Calculations show that it has low antenna Q and operates in the regime of global resonance overlapping. For fundamental harmonic heating scenario only a small portion of the wave energy transits through the cyclotron layer and penetrates to the central part of the trap. The power deposition is peaked at the plasma core. The calculations show that this scenario is prospective for practical implementation in large mirror devices. First results of numerical calculations for second harmonic heating are reported. (author)

  16. Radio frequency reflectometry and charge sensing of a precision placed donor in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Hile, Samuel J., E-mail: samhile@gmail.com; House, Matthew G.; Peretz, Eldad; Verduijn, Jan; Widmann, Daniel; Kobayashi, Takashi; Rogge, Sven; Simmons, Michelle Y., E-mail: michelle.simmons@unsw.edu.au [Centre for Quantum Computation and Communication Technology - CQC" 2T, School of Physics, University of New South Wales, Sydney 2052 (Australia)

    2015-08-31

    We compare charge transitions on a deterministic single P donor in silicon using radio frequency reflectometry measurements with a tunnel coupled reservoir and DC charge sensing using a capacitively coupled single electron transistor (SET). By measuring the conductance through the SET and comparing this with the phase shift of the reflected radio frequency (RF) excitation from the reservoir, we can discriminate between charge transfer within the SET channel and tunneling between the donor and reservoir. The RF measurement allows observation of donor electron transitions at every charge degeneracy point in contrast to the SET conductance signal where charge transitions are only observed at triple points. The tunnel coupled reservoir has the advantage of a large effective lever arm (∼35%), allowing us to independently extract a neutral donor charging energy ∼62 ± 17 meV. These results demonstrate that we can replace three terminal transistors by a single terminal dispersive reservoir, promising for high bandwidth scalable donor control and readout.

  17. Influence of radio frequency power on structure and ionic conductivity of LiPON thin films

    Indian Academy of Sciences (India)

    Zongqian Hu; Dezhan Li; Kai Xie

    2008-08-01

    Lithium phosphorus oxynitride (LiPON) thin films as solid electrolytes were prepared by radio frequency magnetron sputtering of a Li3PO4 target in ambient nitrogen atmosphere. The influence of radio frequency (rf) power on the structure and the ionic conductivity of LiPON thin films has been investigated. The morphology, composition, structure and ionic conductivity of thin films were characterized by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and a.c. impedance measurement. It was found that ionic conductivity of LiPON thin films increases with N content in thin films. XPS measurements reveal that ionic conductivity also keeps relativity with the structure of thin films. Higher the t/d ratio, higher will be the ionic conductivity of LiPON thin films. And both of them can be improved by increasing rf power from 1.5 W/cm2 to 5.5 W/cm2.

  18. COMPARISON OF RADIO-FREQUENCY INTERFERENCE MITIGATION STRATEGIES FOR DISPERSED PULSE DETECTION

    International Nuclear Information System (INIS)

    Impulsive radio-frequency signals from astronomical sources are dispersed by the frequency-dependent index of refraction of the interstellar media and so appear as chirped signals when they reach Earth. Searches for dispersed impulses have been limited by false detections due to radio-frequency interference (RFI) and, in some cases, artifacts of the instrumentation. Many authors have discussed techniques to excise or mitigate RFI in searches for fast transients, but comparisons between different approaches are lacking. This work develops RFI mitigation techniques for use in searches for dispersed pulses, employing data recorded in a 'Fly's Eye' mode of the Allen Telescope Array as a test case. We gauge the performance of several RFI mitigation techniques by adding dispersed signals to data containing RFI and comparing false alarm rates at the observed signal-to-noise ratios of the added signals. We find that Huber filtering is most effective at removing broadband interferers, while frequency centering is most effective at removing narrow frequency interferers. Neither of these methods is effective over a broad range of interferers. A method that combines Huber filtering and adaptive interference cancelation provides the lowest number of false positives over the interferers considered here. The methods developed here have application to other searches for dispersed pulses in incoherent spectra, especially those involving multiple beam systems.

  19. Comparison of Radio-frequency Interference Mitigation Strategies for Dispersed Pulse Detection

    Science.gov (United States)

    Hogden, John; Vander Wiel, Scott; Bower, Geoffrey C.; Michalak, Sarah; Siemion, Andrew; Werthimer, Daniel

    2012-03-01

    Impulsive radio-frequency signals from astronomical sources are dispersed by the frequency-dependent index of refraction of the interstellar media and so appear as chirped signals when they reach Earth. Searches for dispersed impulses have been limited by false detections due to radio-frequency interference (RFI) and, in some cases, artifacts of the instrumentation. Many authors have discussed techniques to excise or mitigate RFI in searches for fast transients, but comparisons between different approaches are lacking. This work develops RFI mitigation techniques for use in searches for dispersed pulses, employing data recorded in a "Fly's Eye" mode of the Allen Telescope Array as a test case. We gauge the performance of several RFI mitigation techniques by adding dispersed signals to data containing RFI and comparing false alarm rates at the observed signal-to-noise ratios of the added signals. We find that Huber filtering is most effective at removing broadband interferers, while frequency centering is most effective at removing narrow frequency interferers. Neither of these methods is effective over a broad range of interferers. A method that combines Huber filtering and adaptive interference cancelation provides the lowest number of false positives over the interferers considered here. The methods developed here have application to other searches for dispersed pulses in incoherent spectra, especially those involving multiple beam systems.

  20. Radio-frequency heating of sloshing ions in a straight field line mirror

    International Nuclear Information System (INIS)

    Sloshing ions, the energetic ions with a velocity distribution concentrated to a certain pitch-angle, play an important role in plasma confinement in mirrors. They are normally produced in mirror traps with neutral beam injection. They also could be generated by ion-cyclotron heating. In the present report two radio-frequency heating scenarios to sustain a sloshing ion population in a newly proposed mirror device, the straight field line mirror, are examined. The first one consists in the ion cyclotron heating in two-ion species plasma using longitudinal wave conversion and fundamental harmonic heating of deuterium ions in tritium plasma. This scheme provides efficient ion heating for high deuterium minority' concentration without substantial power deposition to the electrons. The second scenario is based on second harmonic heating of deuterium ions. The study uses numerical 3D calculations for the time-harmonic boundary problem for Maxwell's equations. For the radio-frequency heating in both schemes, a simple strap antenna is used. Calculations show that it has low antenna Q and operates in the regime of global resonance overlapping. For fundamental harmonic heating scenario only a small portion of the wave energy transits through the cyclotron layer and penetrates to the central part of the trap. The power deposition is peaked at the plasma core. The calculations show that this scenario is prospective for practical implementation in large mirror devices. First results of numerical calculations for second harmonic heating are reported. (author)

  1. Comparison of the radio frequency hollow cathode to the microwave antenna discharge for plasma processing

    International Nuclear Information System (INIS)

    Two nonconventional systems, the radio frequency hollow cathode discharge (RHCD) and the microwave antenna discharge (MWAD), with almost identical geometry of electrodes generating a nitrogen plasma at power level up to 60 W were compared. Both systems were used for deposition of nitride films at similar experimental parameters. The Al--N films were deposited in the RHCD system by reactive physical vapor deposition (PVD) using an Al radio frequency hollow cathode and the CNx films were deposited in the MWAD system by plasma activated chemical vapor deposition (PACVD) from N2+1% (alternatively 0.5% or 0.4%) C2H2 gas mixtures. The vibrational temperatures of nitrogen molecules in both systems were compared as functions of experimental parameters and discussed with respect to the film growth rates in the particular systems. It was found that irrespective of frequency difference of two orders of magnitude the vibrational temperatures of nitrogen molecules were similar, between 3000 and 4600 K, in both systems at similar experimental conditions. However, shapes of dependences of the vibrational temperature on particular parameters were different, due to different plasma generation principles. The nitride film growth rates were found to correlate to the vibrational temperatures of nitrogen molecules, but their dependences on experimental parameters were affected by specific features of the plasma generation in individual systems as well as by different mechanisms of the PVD and the PACVD of films. copyright 2001 American Institute of Physics

  2. Resonant-frequency discharge in a multi-cell radio frequency cavity

    Energy Technology Data Exchange (ETDEWEB)

    Popovic, S; Upadhyay, J; Mammosser, J; Nikolic, M; Vuskovic, L

    2014-11-07

    We are reporting experimental results on microwave discharge operating at resonant frequency in a multi-cell radio frequency (RF) accelerator cavity. Although the discharge operated at room temperature, the setup was constructed so that it could be used for plasma generation and processing in fully assembled active superconducting radio-frequency (SRF) cryomodule (in situ operation). This discharge offers an efficient mechanism for removal of a variety of contaminants, organic or oxide layers, and residual particulates from the interior surface of RF cavities through the interaction of plasma-generated radicals with the cavity walls. We describe resonant RF breakdown conditions and address the problems related to generation and sustaining the multi-cell cavity plasma, which are breakdown and resonant detuning. We have determined breakdown conditions in the cavity, which was acting as a plasma vessel with distorted cylindrical geometry. We discuss the spectroscopic data taken during plasma removal of contaminants and use them to evaluate plasma parameters, characterize the process, and estimate the volatile contaminant product removal.

  3. Quantum mechanics in rotating-radio-frequency traps and Penning traps with a quadrupole rotating field

    International Nuclear Information System (INIS)

    Quantum-mechanical analysis of ion motion in a rotating-radio-frequency (rrf) trap or in a Penning trap with a quadrupole rotating field is carried out. Rrf traps were introduced by Hasegawa and Bollinger [Phys. Rev. A 72, 043404 (2005)]. The classical motion of a single ion in this trap is described by only trigonometric functions, whereas in the conventional linear radio-frequency (rf) traps it is by the Mathieu functions. Because of the simple classical motion in the rrf trap, it is expected that the quantum-mechanical analysis of the rrf traps is also simple compared to that of the linear rf traps. The analysis of Penning traps with a quadrupole rotating field is also possible in a way similar to the rrf traps. As a result, the Hamiltonian in these traps is the same as the two-dimensional harmonic oscillator, and energy levels and wave functions are derived as exact results. In these traps, it is found that one of the vibrational modes in the rotating frame can have negative energy levels, which means that the zero-quantum-number state (''ground'' state) is the highest energy state.

  4. Supplying the Power Requirements to a Sensor Network Using Radio Frequency Power Transfer

    Directory of Open Access Journals (Sweden)

    Steven Percy

    2012-06-01

    Full Text Available Wireless power transmission is a method of supplying power to small electronic devices when there is no wired connection. One way to increase the range of these systems is to use a directional transmitting antenna, the problem with this approach is that power can only be transmitted through a narrow beam and directly forward, requiring the transmitter to always be aligned with the sensor node position. The work outlined in this article describes the design and testing of an autonomous radio frequency power transfer system that is capable of rotating the base transmitter to track the position of sensor nodes and transferring power to that sensor node. The system’s base station monitors the node’s energy levels and forms a charge queue to plan charging order and maintain energy levels of the nodes. Results show a radio frequency harvesting circuit with a measured S11 value of −31.5 dB and a conversion efficiency of 39.1%. Simulation and experimentation verified the level of power transfer and efficiency. The results of this work show a small network of three nodes with different storage types powered by a central base node.

  5. Radio-frequency-sheath-driven edge plasma convection and interaction with the H mode

    International Nuclear Information System (INIS)

    It is shown that radio-frequency (rf) antenna sheaths can bias the edge plasma potential and drive steady-state convective cells in the scrape-off layer (SOL). The resulting ExB convective flow opposes the direction of the sheared flow in the SOL induced by the radially decaying Bohm sheath potential. A two-dimensional fluid simulation shows that the interaction of the opposing poloidal flows produces secondary vortices, which connect the edge of the confined plasma to the antenna limiters, when the antenna--plasma separation is typically of order a few times the local electron skin depth at the antenna. Estimates for typical tokamak edge parameters suggest that the transit time of particles and energy across these vortices is rapid enough to cause the broadening of SOL density and temperature profiles observed during high-power heating with ion cyclotron range of frequency (ICRF) antennas in monopole phasing. Radio-frequency-sheath-driven convection is also a good candidate to explain the phasing dependence of the global confinement properties of ICRF H modes on the Joint European Torus (JET) [Fusion Technol. 11, 13 (1987)]. A comparison of the JET H-mode data with the theoretical modeling supports this idea and suggests that ICRF convection may be a useful tool to spread the heat deposition in the divertor and to extend the lifetime of the H mode

  6. Ge Nanoislands Grown by Radio Frequency Magnetron Sputtering: Comprehensive Investigation of Surface Morphology and Optical Properties

    Directory of Open Access Journals (Sweden)

    Alireza Samavati

    2015-01-01

    Full Text Available The comprehensive investigation of the effect of growth parameters on structural and optical properties of Si-based single layer Ge nanoislands grown via Stranski-Krastanov mechanism employing radio frequency magnetron sputtering due to its high deposition rate, easy procedure, economical cost, and safety is carried out. The estimated width and height of Ge nanoislands produced by this technique are in the range of ∼8 to ∼30 and ∼2 to 8 nm, respectively. Varieties parameters are manipulated to optimize the surface morphology and structural and optical behavior of Ge nanoislands. The resulted nanoislands are analyzed using various analytical techniques including atomic force microscope, X-ray diffraction, energy dispersive X-ray spectroscopy, room temperature photoluminescence, and Raman spectroscopy. The optimum parameters for growing high quality samples having high number density and homogenous and small size distribution are found to be 400°C for substrate temperature, 300 sec for deposition time, 10 sccm for Ar flow, and 100 W for radio frequency power. The excellent features of the results suggest that our systematic investigation on the organized growth factors and their effects on surface parameters and photoluminescence emission energy may constitute a basis for the tunable growth of Ge nanoislands (100 nanoislands suitable in nanophotonics.

  7. Observation of the glow-to-arc transitions

    Science.gov (United States)

    Watanabe, Shigeru; Saito, Shigeki; Takahashi, Kunio; Onzawa, Tadao

    2002-10-01

    Researches of the glow-to-arc transitions have been required for a new development of the welding technology in low current. It is important to clarify the characteristics of plasma in the transitions because there have been few reports investigated the transitions in detail. The glow-to-arc transitions were observed in argon at atmospheric pressure. The Th-W electrodes of 1 mm in a diameter are used. Both of the electrodes are needle-shaped and set in a quartz tube coaxially. Plasma is generated between the electrodes with the gap spacing of 1 mm. A DC power supply has been applying constant voltage of 600 V during the discharge. A high-speed camera is used to record the images of plasma in the transitions with the measurement of voltage and current between the electrodes. As a result, two things were confirmed for the behavior of the glow-to-arc transition. First, plasma extended over the cathode surface in the transition from the glow to the arc. Second, temperature in the tip of the cathode would increase gradually during the glow and decrease during the arc.

  8. High-energy sources at low radio frequency: the Murchison Widefield Array view of Fermi blazars

    Science.gov (United States)

    Giroletti, M.; Massaro, F.; D'Abrusco, R.; Lico, R.; Burlon, D.; Hurley-Walker, N.; Johnston-Hollitt, M.; Morgan, J.; Pavlidou, V.; Bell, M.; Bernardi, G.; Bhat, R.; Bowman, J. D.; Briggs, F.; Cappallo, R. J.; Corey, B. E.; Deshpande, A. A.; Ewall-Rice, A.; Emrich, D.; Gaensler, B. M.; Goeke, R.; Greenhill, L. J.; Hazelton, B. J.; Hindson, L.; Kaplan, D. L.; Kasper, J. C.; Kratzenberg, E.; Feng, L.; Jacobs, D.; Kudryavtseva, N.; Lenc, E.; Lonsdale, C. J.; Lynch, M. J.; McKinley, B.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Oberoi, D.; Offringa, A. R.; Ord, S. M.; Pindor, B.; Prabu, T.; Procopio, P.; Riding, J.; Rogers, A. E. E.; Roshi, A.; Udaya Shankar, N.; Srivani, K. S.; Subrahmanyan, R.; Tingay, S. J.; Waterson, M.; Wayth, R. B.; Webster, R. L.; Whitney, A. R.; Williams, A.; Williams, C. L.

    2016-04-01

    Context. Low-frequency radio arrays are opening a new window for the study of the sky, both to study new phenomena and to better characterize known source classes. Being flat-spectrum sources, blazars are so far poorly studied at low radio frequencies. Aims: We characterize the spectral properties of the blazar population at low radio frequency, compare the radio and high-energy properties of the gamma-ray blazar population, and search for radio counterparts of unidentified gamma-ray sources. Methods: We cross-correlated the 6100 deg2 Murchison Widefield Array Commissioning Survey catalogue with the Roma blazar catalogue, the third catalogue of active galactic nuclei detected by Fermi-LAT, and the unidentified members of the entire third catalogue of gamma-ray sources detected by Fermi-LAT. When available, we also added high-frequency radio data from the Australia Telescope 20 GHz catalogue. Results: We find low-frequency counterparts for 186 out of 517 (36%) blazars, 79 out of 174 (45%) gamma-ray blazars, and 8 out of 73 (11%) gamma-ray blazar candidates. The mean low-frequency (120-180 MHz) blazar spectral index is ⟨αlow⟩ = 0.57 ± 0.02: blazar spectra are flatter than the rest of the population of low-frequency sources, but are steeper than at ~GHz frequencies. Low-frequency radio flux density and gamma-ray energy flux display a mildly significant and broadly scattered correlation. Ten unidentified gamma-ray sources have a (probably fortuitous) positional match with low radio frequency sources. Conclusions: Low-frequency radio astronomy provides important information about sources with a flat radio spectrum and high energy. However, the relatively low sensitivity of the present surveys still misses a significant fraction of these objects. Upcoming deeper surveys, such as the GaLactic and Extragalactic All-Sky MWA (GLEAM) survey, will provide further insight into this population. Tables 5-7 are only available at the CDS via anonymous ftp to http

  9. Percutaneous radio-frequency thermocoagulation of the Gasserian ganglion guided by high-speed real-time CT fluoroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Koizuka, Shiro [Gunma University Graduate School of Medicine, Department of Anesthesiology, Maebashi (Japan); Gunma University Hospital, Department of Anesthesiology, Maebashi (Japan); Saito, Shigeru; Sekimoto, Kenichi; Tobe, Masaru; Obata, Hideaki [Gunma University Graduate School of Medicine, Department of Anesthesiology, Maebashi (Japan); Koyama, Yoshinori [Gunma University Graduate School of Medicine, Department of Diagnostic Radiology and Nuclear Medicine, Maebashi (Japan)

    2009-09-15

    Although Gasserian ganglion block is an established treatment for trigeminal neuralgia, the foramen ovale cannot always be clearly visualized by classical X-ray radiography. We present a new method for percutaneous radio-frequency thermocoagulation of the Gasserian ganglion, in which computed tomography (CT) fluoroscopy is used to guide needle placement. In the present study, 15 patients with trigeminal neuralgia underwent percutaneous radio-frequency thermocoagulation of the Gasserian ganglion guided by high-speed real-time CT fluoroscopy. Trigeminal neuralgia was improved in all patients after treatment without any severe complications. Moderate dysesthesia occurred in only one case. CT fluoroscopy-guided percutaneous radio-frequency thermocoagulation of the Gasserian ganglion was safe, quick, and effective for patients with intractable idiopathic trigeminal neuralgia. (orig.)

  10. Percutaneous radio-frequency thermocoagulation of the Gasserian ganglion guided by high-speed real-time CT fluoroscopy

    International Nuclear Information System (INIS)

    Although Gasserian ganglion block is an established treatment for trigeminal neuralgia, the foramen ovale cannot always be clearly visualized by classical X-ray radiography. We present a new method for percutaneous radio-frequency thermocoagulation of the Gasserian ganglion, in which computed tomography (CT) fluoroscopy is used to guide needle placement. In the present study, 15 patients with trigeminal neuralgia underwent percutaneous radio-frequency thermocoagulation of the Gasserian ganglion guided by high-speed real-time CT fluoroscopy. Trigeminal neuralgia was improved in all patients after treatment without any severe complications. Moderate dysesthesia occurred in only one case. CT fluoroscopy-guided percutaneous radio-frequency thermocoagulation of the Gasserian ganglion was safe, quick, and effective for patients with intractable idiopathic trigeminal neuralgia. (orig.)

  11. Large-signal model of the bilayer graphene field-effect transistor targeting radio-frequency applications: Theory versus experiment

    Science.gov (United States)

    Pasadas, Francisco; Jiménez, David

    2015-12-01

    Bilayer graphene is a promising material for radio-frequency transistors because its energy gap might result in a better current saturation than the monolayer graphene. Because the great deal of interest in this technology, especially for flexible radio-frequency applications, gaining control of it requires the formulation of appropriate models for the drain current, charge, and capacitance. In this work, we have developed them for a dual-gated bilayer graphene field-effect transistor. A drift-diffusion mechanism for the carrier transport has been considered coupled with an appropriate field-effect model taking into account the electronic properties of the bilayer graphene. Extrinsic resistances have been included considering the formation of a Schottky barrier at the metal-bilayer graphene interface. The proposed model has been benchmarked against experimental prototype transistors, discussing the main figures of merit targeting radio-frequency applications.

  12. Large-signal model of the bilayer graphene field-effect transistor targeting radio-frequency applications: Theory versus experiment

    Energy Technology Data Exchange (ETDEWEB)

    Pasadas, Francisco, E-mail: Francisco.Pasadas@uab.cat; Jiménez, David [Departament d' Enginyeria Electrònica, Escola d' Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra (Spain)

    2015-12-28

    Bilayer graphene is a promising material for radio-frequency transistors because its energy gap might result in a better current saturation than the monolayer graphene. Because the great deal of interest in this technology, especially for flexible radio-frequency applications, gaining control of it requires the formulation of appropriate models for the drain current, charge, and capacitance. In this work, we have developed them for a dual-gated bilayer graphene field-effect transistor. A drift-diffusion mechanism for the carrier transport has been considered coupled with an appropriate field-effect model taking into account the electronic properties of the bilayer graphene. Extrinsic resistances have been included considering the formation of a Schottky barrier at the metal-bilayer graphene interface. The proposed model has been benchmarked against experimental prototype transistors, discussing the main figures of merit targeting radio-frequency applications.

  13. Large-signal model of the bilayer graphene field-effect transistor targeting radio-frequency applications: Theory versus experiment

    International Nuclear Information System (INIS)

    Bilayer graphene is a promising material for radio-frequency transistors because its energy gap might result in a better current saturation than the monolayer graphene. Because the great deal of interest in this technology, especially for flexible radio-frequency applications, gaining control of it requires the formulation of appropriate models for the drain current, charge, and capacitance. In this work, we have developed them for a dual-gated bilayer graphene field-effect transistor. A drift-diffusion mechanism for the carrier transport has been considered coupled with an appropriate field-effect model taking into account the electronic properties of the bilayer graphene. Extrinsic resistances have been included considering the formation of a Schottky barrier at the metal-bilayer graphene interface. The proposed model has been benchmarked against experimental prototype transistors, discussing the main figures of merit targeting radio-frequency applications

  14. Generating multiple orbital angular momentum vortex beams using a metasurface in radio frequency domain

    Science.gov (United States)

    Yu, Shixing; Li, Long; Shi, Guangming; Zhu, Cheng; Shi, Yan

    2016-06-01

    In this paper, an electromagnetic metasurface is designed, fabricated, and experimentally demonstrated to generate multiple orbital angular momentum (OAM) vortex beams in radio frequency domain. Theoretical formula of compensated phase-shift distribution is deduced and used to design the metasurface to produce multiple vortex radio waves in different directions with different OAM modes. The prototype of a practical configuration of square-patch metasurface is designed, fabricated, and measured to validate the theoretical analysis at 5.8 GHz. The simulated and experimental results verify that multiple OAM vortex waves can be simultaneously generated by using a single electromagnetic metasurface. The proposed method paves an effective way to generate multiple OAM vortex waves in radio and microwave wireless communication applications.

  15. Low temperature laser scanning microscopy of a superconducting radio-frequency cavity

    Science.gov (United States)

    Ciovati, G.; Anlage, Steven M.; Baldwin, C.; Cheng, G.; Flood, R.; Jordan, K.; Kneisel, P.; Morrone, M.; Nemes, G.; Turlington, L.; Wang, H.; Wilson, K.; Zhang, S.

    2012-03-01

    An apparatus was developed to obtain, for the first time, 2D maps of the surface resistance of the inner surface of an operating superconducting radio-frequency niobium cavity by a low-temperature laser scanning microscopy technique. This allows identifying non-uniformities of the surface resistance with a spatial resolution of about 2.4 mm and surface resistance resolution of ˜1 μΩ at 3.3 GHz. A signal-to-noise ratio of about 10 dB was obtained with 240 mW laser power and 1 Hz modulation frequency. The various components of the apparatus, the experimental procedure and results are discussed in detail in this contribution.

  16. Overall performance evaluation using an equivalent circuit model for radio-frequency single-electron transistors

    International Nuclear Information System (INIS)

    Charge sensitivities of a radio-frequency single-electron transistor (RF-SET) by using amplitude (AD) and phase-shift detection (PSD) of the reflected RF signals were experimentally studied. It was found that AD is most sensitive at the resonant frequency while PSD is most sensitive at a frequency slightly off the resonance. The best PSD sensitivity is better than the best AD one when the quality factor of a tank circuit is higher than 10; the higher Q-value is, the superior PSD. The maximal change in reflection amplitude and phase-shift were found proportional to the SET conductance change. The above experimental findings were confirmed by the calculation based on an equivalent circuit model

  17. Performance Analysis of a Hardware Implemented Complex Signal Kurtosis Radio-Frequency Interference Detector

    Science.gov (United States)

    Schoenwald, Adam J.; Bradley, Damon C.; Mohammed, Priscilla N.; Piepmeier, Jeffrey R.; Wong, Mark

    2016-01-01

    In the field of microwave radiometry, Radio Frequency Interference (RFI) consistently degrades the value of scientific results. Through the use of digital receivers and signal processing, the effects of RFI on scientific measurements can be reduced depending on certain circumstances. As technology allows us to implement wider band digital receivers for radiometry, the problem of RFI mitigation changes. Our work focuses on finding a detector that outperforms real kurtosis in wide band scenarios. The algorithm implemented is a complex signal kurtosis detector which was modeled and simulated. The performance of both complex and real signal kurtosis is evaluated for continuous wave, pulsed continuous wave, and wide band quadrature phase shift keying (QPSK) modulations. The use of complex signal kurtosis increased the detectability of interference.

  18. Theoretical studies of the heating of toroidal plasmas with radio frequency electromagnetic radiation. Final report

    International Nuclear Information System (INIS)

    The continuation of a program of theoretical studies of the heating of toroidal plasmas with radio frequency (RF) electromagnetic radiation is proposed. Funding for this project first began on September 3, 1981, and will expire on April 2, 1982. A summary of the principal accomplishments of the first five months of the project is presented. These include the acquisition of computer terminals and modems, the implementation of existing codes on the MFECC C Cray Computer, the extension of the LHTOR lower hybrid toroidal ray tracing code to the full electromagnetic dispersion relation, the implementation of graphic output from the code, the beginning of extensive parameter studies, the beginning of an analytical treatment of the mode conversion layer associated with singular harmonic absorption, and the introduction of a graduate student into the program

  19. Multifrequency Magneto-optic Bragg Diffraction and Radio Frequency Signal Parallel Processing

    Institute of Scientific and Technical Information of China (English)

    SHANG Dan; WU Bao-jian; QIU Kun

    2008-01-01

    Magneto-optic(MO) coupling of guided optical waves with microwave magnetostatic waves(MSWs) simultaneously excited by multiple radio frequency(RF) signals can lead to multifrequency diffraction effects and then parallel processing of RF signals can be realized by using of the characteristics that diffraction efficiencies(Des) are approximately in direct proportion to RF signals intensities and diffraction angles are related to frequencies of the corresponding RF signals within linear MO interaction region. In this paper, studied is the multifrequency MO Bragg diffraction in first-order MO interaction approximation, and obtained was the approximate analytical expression for principle diffraction efficiency(PDE). Also, put forward was a parallel imaging method of relative intensity of RF signals based on single-frequency diffraction. By calculation and analysis, it is shown that the relative error is not more than 0.3 dB for the case of three RF signals within the frequency space of 60 MHz.

  20. Temperature of hydrogen radio frequency plasma under dechlorination process of polychlorinated biphenyls

    Energy Technology Data Exchange (ETDEWEB)

    Inada, Y., E-mail: inada@hvg.t.u-tokyo.ac.jp; Abe, K.; Kumada, A.; Hidaka, K. [Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Amano, K.; Itoh, K.; Oono, T. [R and D Center, Tokyo Electric Power Company, 4-1 Egasaki-cho, Tsurumi-ku, Yokohama 230-8510 (Japan)

    2014-10-27

    It has been reported that RF (radio frequency) hydrogen plasmas promote the dechlorination process of PCBs (polychlorinated biphenyls) under irradiation of MW (microwave). A relative emission intensity spectroscope system was used for single-shot imaging of two-dimensional temperature distributions of RF hydrogen plasmas generated in chemical solutions with several mixing ratios of isopropyl alcohol (IPA) and insulation oil under MW irradiation. Our experimental results showed that the plasma generation frequencies for the oil-contaminating solutions were higher than that for the pure IPA solution. In addition, the plasma temperature in the compound liquids including both oil and IPA was higher than that in the pure IPA and oil solutions. A combination of the plasma temperature measurements and plasma composition analysis indicated that the hydrogen radicals generated in a chemical solution containing the equal volumes of IPA and oil were almost the same amounts of H and H{sup +}, while those produced in the other solutions were mainly H.

  1. Beam Emittance Measurements for the Low-Energy Demonstration Accelerator Radio-Frequency Quadrupole

    OpenAIRE

    Schulze, M. E.; Gilpatrick, J.D.; Lysenko, W. P.; Rybarcyk, L. J.; Schneider, J. D.; Smith, Jr., Norman Austin; You, L. M.

    2000-01-01

    The Low-Energy Demonstration Accelerator (LEDA) radio-frequency quadrupole (RFQ) is a 100% duty factor (CW) linac that delivers >100 mA of H+ beam at 6.7 MeV. The 8-m-long, 350-MHz RFQ structure accelerates a dc, 75-keV, 110-mA H+ beam from the LEDA injector with >90% transmission. LEDA [1,2] consists of a 75-keV proton injector, 6.7-MeV, 350-MHz CW RFQ with associated high-power and low-level rf systems, a short high-energy beam transport (HEBT) and high-power (670-kW CW) beam stop. The beam...

  2. Design of high power radio frequency radial combiner for proton accelerator.

    Science.gov (United States)

    Jain, Akhilesh; Sharma, Deepak Kumar; Gupta, Alok Kumar; Hannurkar, P R

    2009-01-01

    A simplified design method has been proposed for systematic design of novel radio frequency (rf) power combiner and divider, incorporating radial slab-line structure, without using isolation resistor and external tuning mechanism. Due to low insertion loss, high power capability, and rigid mechanical configuration, this structure is advantageous for modern solid state rf power source used for feeding rf energy to superconducting accelerating structures. Analysis, based on equivalent circuit and radial transmission line approximation, provides simple design formula for calculating combiner parameters. Based on this method, novel 8-way and 16-way power combiners, with power handling capability of 4 kW, have been designed, as part of high power solid state rf amplifier development. Detailed experiments showed good performance in accordance with theory. PMID:19191467

  3. Radio-frequency discharges in oxygen: I. Particle-based modelling

    International Nuclear Information System (INIS)

    In this series of three papers we present results from a combined experimental and theoretical, particle-based study to quantitatively describe capacitively coupled radio-frequency discharges in oxygen. The particle-in-cell Monte Carlo model on which the theoretical description is based is described in this paper. It treats space charge fields and transport processes on an equal footing with the most important plasma-chemical reactions. For given external voltage and pressure, the model determines the electric potential within the discharge and the distribution functions for electrons, negatively charged atomic oxygen and positively charged molecular oxygen. Previously used scattering and reaction cross section data are critically assessed and in some cases modified. To validate our model, we compare the densities in the bulk of the discharge with experimental data and find good agreement, indicating that essential aspects of an oxygen discharge are captured

  4. Electric field and radio frequency measurements for rocket engine health monitoring applications

    Science.gov (United States)

    Valenti, Elizabeth L.

    1992-01-01

    Electric-field (EF) and radio-frequency (RF) emissions generated in the exhaust plumes of the diagnostic testbed facility thruster (DTFT) and the SSME are examined briefly for potential applications to plume diagnostics and engine health monitoring. Hypothetically, anomalous engine conditions could produce measurable changes in any characteristic EF and RF spectral signatures identifiable with a 'healthly' plumes. Tests to determine the presence of EF and RF emissions in the DTFT and SSME exhaust plumes were conducted. EF and RF emissions were detected using state-of-the-art sensors. Analysis of limited data sets show some apparent consistencies in spectral signatures. Significant emissions increases were detected during controlled tests using dopants injected into the DTFT.

  5. Heat Transfer During Radio Frequency Inductively Coupled Plasma Deposition of Tungsten

    Institute of Scientific and Technical Information of China (English)

    JIANG Xianliang; M.I.BOULOS

    2007-01-01

    Particle melting and substrate temperature are important in controlling deposited density and residual stress in thermal plasma deposition of refractory materials.In this paper,both the heating and cooling behaviours of tungsten particles inside a radio frequency inductively coupled plasma(ICP)and the plasma heat flux to the substrate were investigated.The distribution of the plasma-generated heat on device,powder injection probe,deposition chamber,and substrate Was determined by measuring the water flow rate and the flow-in and flow-out water temperatures in the four parts.Substrate temperature Was measured by a two-colour pyrometer during the ICP deposition of tungsten.Experimental results show that the heat flux to the substrate accounts for about 20% of the total plasma energy,the substrate temperature can reach as high as 2100 K,and the heat loss by radiation is significant in the plasma deposition of tungsten.

  6. Flux pinning characteristics in cylindrical ingot niobium used in superconducting radio frequency cavity fabrication

    CERN Document Server

    Dhavale, Asavari S; Polyanskii, Anatolii A; Ciovati, Gianluigi

    2012-01-01

    We present the results of from DC magnetization and penetration depth measurements of cylindrical bulk large-grain (LG) and fine-grain (FG) niobium samples used for the fabrication of superconducting radio frequency (SRF) cavities. The surface treatment consisted of electropolishing and low temperature baking as they are typically applied to SRF cavities. The magnetization data were fitted using a modified critical state model. The critical current density Jc and pinning force Fp are calculated from the magnetization data and their temperature dependence and field dependence are presented. The LG samples have lower critical current density and pinning force density compared to FG samples which implies a lower flux trapping efficiency. This effect may explain the lower values of residual resistance often observed in LG cavities than FG cavities.

  7. Nanostructural features affecting superconducting radio frequency niobium cavities revealed using TEM and EELS

    CERN Document Server

    Trenikhina, Y; Kwon, J; Zuo, J -M; Zasadzinski, J F

    2015-01-01

    Nanoscale defect structure within the magnetic penetration depth of ~100nm is key to the performance limitations of niobium superconducting radio frequency (SRF) cavities. Using a unique combination of advanced thermometry during cavity RF measurements, and TEM structural and compositional characterization of the samples extracted from cavity walls, we discover the existence of nanoscale hydrides in electropolished cavities limited by the high field Q slope, and show the decreased hydride formation in the electropolished cavity after 120C baking. Furthermore, we demonstrate that adding 800C hydrogen degassing followed by light buffered chemical polishing restores the hydride formation to the pre-120C bake level. We also show absence of niobium oxides along the grain boundaries and the modifications of the surface oxide upon 120C bake.

  8. ION cyclotron radio frequency systems and performance on the Tandem Mirror Experiment-Upgrade

    International Nuclear Information System (INIS)

    High power ion cyclotron radio frequency (ICRF) systems are now gaining greater attention than before as prime driver ion heating systems. Lawrence Livermore National Laboratory (LLNL) has installed a 200 kW high frequency (HF) transmitter system on its Tandem Mirror Experiment-Upgrade (TMX-U). This paper describes the system, antenna, controls, and monitoring apparatus. The transmitter operates into a high Q antenna installed in the central cell region of the experiment. It incorporates a dual-port feedback system to automatically adjust the transmitter's output power and allow the maximum consistent with the plasma loading of the antenna. Special techniques have been used to measure, in real-time, the dynamically changing loading values presented by the plasma. From the measurements, the antenna impedance can be optimized for specified plasma density

  9. Radio Frequency Compatibility of an RFID Tag on Glideslope Navigation Receivers

    Science.gov (United States)

    Nguyen, Truong X.; Mielnik, John J.

    2008-01-01

    A process is demonstrated to show compatibility between a radio frequency identification (RFID) tag and an aircraft glideslope (GS) radio receiver. The particular tag chosen was previously shown to have significant peak spurious emission levels that far exceeded the emission limits in the GS aeronautical band. The spurious emissions are emulated in the study by capturing the RFID fundamental transmission and playing back the signal in the GS band. The signal capturing and playback are achieved with a vector signal generator and a spectrum analyzer that can output the in-phase and quadrature components (IQ). The simulated interference signal is combined with a desired GS signal before being injected into a GS receiver s antenna port for interference threshold determination. Minimum desired propagation loss values to avoid interference are then computed and compared against actual propagation losses for several aircraft.

  10. Spin-torque diode radio-frequency detector with voltage tuned resonance

    Energy Technology Data Exchange (ETDEWEB)

    Skowroński, Witold, E-mail: skowron@agh.edu.pl; Frankowski, Marek; Stobiecki, Tomasz [AGH University of Science and Technology, Department of Electronics, Al. Mickiewicza 30, 30-059 Kraków (Poland); Wrona, Jerzy [AGH University of Science and Technology, Department of Electronics, Al. Mickiewicza 30, 30-059 Kraków (Poland); Singulus Technologies, Kahl am Main 63796 (Germany); Ogrodnik, Piotr [Faculty of Physics, Warsaw University of Technology, ul. Koszykowa 75, 00-662 Warsaw (Poland); AGH University of Science and Technology, Department of Electronics, Al. Mickiewicza 30, 30-059 Kraków (Poland); Barnaś, Józef [Faculty of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań (Poland); Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznań (Poland)

    2014-08-18

    We report on a voltage-tunable radio-frequency (RF) detector based on a magnetic tunnel junction (MTJ). The spin-torque diode effect is used to excite and/or detect RF oscillations in the magnetic free layer of the MTJ. In order to reduce the overall in-plane magnetic anisotropy of the free layer, we take advantage of the perpendicular magnetic anisotropy at the interface between ferromagnetic and insulating layers. The applied bias voltage is shown to have a significant influence on the magnetic anisotropy, and thus on the resonance frequency of the device. This influence also depends on the voltage polarity. The obtained results are accounted for in terms of the interplay of spin-transfer-torque and voltage-controlled magnetic anisotropy effects.

  11. Dispersive radio frequency electrometry using Rydberg atoms in a prism-shaped atomic vapor cell

    Science.gov (United States)

    Fan, H. Q.; Kumar, S.; Kübler, H.; Shaffer, J. P.

    2016-05-01

    We introduce a method to measure radio frequency (RF) electric fields (E-fields) using atoms contained in a prism-shaped vapor cell. The method utilizes the concept of electromagnetically induced transparency with Rydberg atoms. The RF E-field induces changes in the index of refraction of the vapor resulting in deflection of the probe laser beam as it passes through the prism-shaped vapor cell. We measured a minimum RF E-field of 8.25 μ {{Vcm}}-1 with a sensitivity of ∼ 46.5 μ {{Vcm}}-1 {{Hz}}-1/2. The experimental results agree with a numerical model that includes dephasing effects. We discuss possible improvements to obtain higher sensitivity for RF E-field measurements.

  12. Upgrade of the radio frequency quadrupole cooler and buncher for the HIE-ISOLDE project

    Science.gov (United States)

    Babcock, Carla; Giles, Tim

    2013-12-01

    The upgrade to the ISOLDE facility, HIE-ISOLDE, will include an upgrade to the RFQCB (radio frequency quadrupole cooler and buncher), the focus of which will be fixing the problems of alignment with the current machine, improving the integrity of the vacuum system, stabilizing the internal gas pressure, and the changes associated with a new position. The beam passage inside the RFQCB has been simulated with an independent code to highlight the importance of the internal gas pressure, to motivate design changes in the new RFQCB and to explain ways to improve the performance of the current machine. The suspected misalignment of ISCOOL has been quantified, and, using a simulation of ions passing through the external injection electrodes, the effect of the misalignment on machine acceptance has been detailed. Plans for the future RFQCB test stand and HIE-ISOLDE installation have been outlined.

  13. Upgrade of the radio frequency quadrupole cooler and buncher for the HIE-ISOLDE project

    CERN Document Server

    Babcock, Carla

    2013-01-01

    The upgrade to the ISOLDE facility, HIE-ISOLDE, will include an upgrade to the RFQCB (radio frequency quadrupole cooler and buncher), the focus of which will be fixing the problems of alignment with the current machine, improving the integrity of the vacuum system, stabilizing the internal gas pressure, and the changes associated with a new position. The beam passage inside the RFQCB has been simulated with an independent code to highlight the importance of the internal gas pressure, to motivate design changes in the new RFQCB and to explain ways to improve the performance of the current machine. The suspected misalignment of ISCOOL has been quantified, and, using a simulation of ions passing through the external injection electrodes, the effect of the misalignment on machine acceptance has been detailed. Plans for the future RFQCB test stand and HIE-ISOLDE installation have been outlined. (C) 2013 Elsevier B.V. All rights reserved.

  14. An Electron Bunch Compression Scheme for a Superconducting Radio Frequency Linear Accelerator Driven Light Source

    International Nuclear Information System (INIS)

    We describe an electron bunch compression scheme suitable for use in a light source driven by a superconducting radio frequency (SRF) linac. The key feature is the use of a recirculating linac to perform the initial bunch compression. Phasing of the second pass beam through the linac is chosen to de-chirp the electron bunch prior to acceleration to the final energy in an SRF linac ('afterburner'). The final bunch compression is then done at maximum energy. This scheme has the potential to circumvent some of the most technically challenging aspects of current longitudinal matches; namely transporting a fully compressed, high peak current electron bunch through an extended SRF environment, the need for a RF harmonic linearizer and the need for a laser heater. Additional benefits include a substantial savings in capital and operational costs by efficiently using the available SRF gradient.

  15. Realization of Radio-Frequency Quadrupole (RFQ) for accelerator program - manufacturing methodology adopted by industry

    International Nuclear Information System (INIS)

    Radio-Frequency Quadrupole (RFQ) linacs are efficient, compact, low energy ion structures, which have found numerous applications. They use electrical RF focusing and can capture, bunch, and transmit high-current ion beams. The RFQ for the Indian Ion Accelerator program is made of Oxygen free electrolytic (OFE) Copper in 4 segments of one meter each. Each segment is realized from 4 segments of 2 Minor and Major Vanes each. The Major and Minor Vanes are machined from OFE Copper blocks in stages with intermediate thermal treatments in vacuum environment for stress relieving and the coolant channel holes are drilled though the entire body. The final machining including the Vane tip modulation is done using special tools on a CNC machine. The Vane tip modulation and other geometrical parameters of the Vanes are inspected using a CMM to ascertain the required accuracy. This paper is aimed at discussing various aspects of RFQ development at BrahMos and the technologies developed

  16. Strong Meissner screening change in superconducting radio frequency cavities due to mild baking

    Energy Technology Data Exchange (ETDEWEB)

    Romanenko, A., E-mail: aroman@fnal.gov; Grassellino, A.; Barkov, F. [Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States); Suter, A.; Salman, Z.; Prokscha, T. [Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland)

    2014-02-17

    We investigate “hot” regions with anomalous high field dissipation in bulk niobium superconducting radio frequency cavities for particle accelerators by using low energy muon spin rotation (LE-μSR) on corresponding cavity cutouts. We demonstrate that superconducting properties at the hot region are well described by the non-local Pippard/BCS model for niobium in the clean limit with a London penetration depth λ{sub L}=23±2 nm. In contrast, a cutout sample from the 120 ∘C baked cavity shows a much larger λ>100 nm and a depth dependent mean free path, likely due to gradient in vacancy concentration. We suggest that these vacancies can efficiently trap hydrogen and hence prevent the formation of hydrides responsible for rf losses in hot regions.

  17. Proposed use of the radio-frequency quadrupole structure to funnel high-current ion beams

    International Nuclear Information System (INIS)

    In this paper, we describe a new approach to funneling beams that are initially accelerated in two radio-frequency quadrupole (RFQ) accelerators. Instead of discrete optical elements, we propose to funnel within an RFQ structure, so that during the funneling process the beam is always confined by periodic transverse focusing. Beams with high space charge experience irreversible emittance growth when they emerge from a periodic focusing system. To alleviate this problem, in the proposed funneling system it should be possible to maintain the same focusing periodicity as that of the accelerators preceding the funnel. Also, instead of conventional deflection systems, we propose to use the properties of a modified RFQ structure to deflect two parallel beams toward each other and to merge them into a single final beam. 1 ref., 3 figs

  18. A computationally assisted spectroscopic technique to measure secondary electron emission coefficients in radio frequency plasmas

    CERN Document Server

    Daksha, M; Schuengel, E; Korolov, I; Derzsi, A; Koepke, M; Donko, Z; Schulze, J

    2016-01-01

    A Computationally Assisted Spectroscopic Technique to measure secondary electron emission coefficients ($\\gamma$-CAST) in capacitively-coupled radio-frequency plasmas is proposed. This non-intrusive, sensitive diagnostic is based on a combination of Phase Resolved Optical Emission Spectroscopy and particle-based kinetic simulations. In such plasmas (under most conditions in electropositive gases) the spatio-temporally resolved electron-impact excitation/ionization rate features two distinct maxima adjacent to each electrode at different times within each RF period. While one maximum is the consequence of the energy gain of electrons due to sheath expansion, the second maximum is produced by secondary electrons accelerated towards the plasma bulk by the sheath electric field at the time of maximum voltage drop across the adjacent sheath. Due to these different excitation/ionization mechanisms, the ratio of the intensities of these maxima is very sensitive to the secondary electron emission coefficient $\\gamma$...

  19. Operating experience of upgraded radio frequency source at 76 MHz coupled to heavy ion RFQ

    International Nuclear Information System (INIS)

    A heavy ion radio frequency quadrupole (RFQ) accelerator has been developed at BARC (BARC). A RF source which was designed and developed at 76 MHz earlier, has been upgraded and coupled to heavy ion RFQ successfully. The DC bias supplies of this source have been replaced with new supplies having high efficiency and well filteration against RF interference (RFI). The driver of main power amplifier has been replaced with indigenously designed and developed unit. The earlier introduced microcontroller based interlock experienced RF noise issues. So, this circuit has been modified with the new circuit. With these modifications, the performance of the RF source was improved. Additionally, a separate low power RF source of around 100+ Watt was designed, developed and integrated with RFQ for its RF conditioning. This paper describes the details of up gradation of technologies implemented and coupling experience of this RF source with heavy ion RFQ. (author)

  20. Emission pattern of an aluminium nitride target for radio frequency magnetron sputtering

    International Nuclear Information System (INIS)

    Thin amorphous aluminium nitride films, (a-AlN) have been produced by radio frequency magnetron sputtering at rf power 120W from a highly pure AlN target. The target is mounted below the substrate holder such that its position can be adjusted inside the vacuum chamber. The emission pattern is determined by means of thickness distribution of the deposited material obtained from optical transmission measurements. Holding a set of the process parameters constant and only varying the target-sample distance a three dimensional emission pattern of the AlN target was determined. The deposition rate and emission pattern for 120W and 180W (studied before) were compared. This comparison allows us to consider the target and shielding dimensions of our magnetron to predict the thickness and the sputtering rate distribution for any process parameter and sample target geometry.