Science.gov

Sample records for plasma internal inductance

  1. Effect of antenna capacitance on the plasma characteristics of an internal linear inductively coupled plasma system

    NASA Astrophysics Data System (ADS)

    Lim, Jong Hyeuk; Kim, Kyong Nam; Park, Jung Kyun; Yeom, Geun Young

    2008-08-01

    This study examined the effect of the antenna capacitance of an inductively coupled plasma (ICP) source, which was varied using an internal linear antenna, on the electrical and plasma characteristics of the ICP source. The inductive coupling at a given rf current increased with decreasing antenna capacitance. This was caused by a decrease in the inner copper diameter of the antenna made from coaxial copper/quartz tubing, which resulted in a higher plasma density and lower plasma potential. By decreasing the diameter of the copper tube from 25to10mm, the plasma density of a plasma source size of 2750×2350mm2 was increased from approximately 8×1010/cm3to1.5×1011/cm3 at 15mTorr Ar and 9kW of rf power.

  2. Effect of Antenna Diameter on the Characteristics of Internal-Type Linear Inductively Coupled Plasma

    NASA Astrophysics Data System (ADS)

    Hyeuk Lim, Jong; Kim, Kyong Nam; Gweon, Gwang Ho; Hong, Seung Pyo; Yeom, Geun Young

    2009-09-01

    In this study, the antenna characteristics of an internal-type, linear, inductively coupled plasma (ICP) source were varied by changing the inner conductor diameter of the ICP antenna composed of an inner conductor enclosed by outer dielectric tubing. The effect of the varied antenna characteristics on the plasma characteristics and the electrical characteristics of the large area plasma source with a substrate area of 2300×2000 mm2 were investigated. The decrease of the antenna conductor diameter from 25 to 10 mm decreased the capacitance of the antenna between the conductor and the dielectric tubing, increased the plasma density, decreased the plasma potential at the same rf power, and improved the plasma uniformity. The increased plasma density and the decreased plasma potential obtained with the smaller antenna conductor diameter were attributed to the increased power transfer efficiency caused by the increased inductive coupling at the same rf power.

  3. Effect of Antenna Diameter on the Characteristics of Internal-Type Linear Inductively Coupled Plasma

    NASA Astrophysics Data System (ADS)

    Lim, Jong Hyeuk; Kim, Kyong Nam; Gweon, Gwang Ho; Hong, Seung Pyo; Yeom, Geun Young

    2009-09-01

    In this study, the antenna characteristics of an internal-type, linear, inductively coupled plasma (ICP) source were varied by changing the inner conductor diameter of the ICP antenna composed of an inner conductor enclosed by outer dielectric tubing. The effect of the varied antenna characteristics on the plasma characteristics and the electrical characteristics of the large area plasma source with a substrate area of 2300× 2000 mm2 were investigated. The decrease of the antenna conductor diameter from 25 to 10 mm decreased the capacitance of the antenna between the conductor and the dielectric tubing, increased the plasma density, decreased the plasma potential at the same rf power, and improved the plasma uniformity. The increased plasma density and the decreased plasma potential obtained with the smaller antenna conductor diameter were attributed to the increased power transfer efficiency caused by the increased inductive coupling at the same rf power.

  4. Low-impedance internal linear inductive antenna for large-area flat panel display plasma processing

    SciTech Connect

    Kim, K.N.; Jung, S.J.; Lee, Y.J.; Yeom, G.Y.; Lee, S.H.; Lee, J.K.

    2005-03-15

    An internal-type linear inductive antenna, that is, a double-comb-type antenna, was developed for a large-area plasma source having the size of 1020 mmx830 mm, and high density plasmas on the order of 2.3x10{sup 11} cm{sup -3} were obtained with 15 mTorr Ar at 5000 W of inductive power with good plasma stability. This is higher than that for the conventional serpentine-type antenna, possibly due to the low impedance, resulting in high efficiency of power transfer for the double-comb antenna type. In addition, due to the remarkable reduction of the antenna length, a plasma uniformity of less than 8% was obtained within the substrate area of 880 mmx660 mm at 5000 W without having a standing-wave effect.

  5. Uniformity of internal linear-type inductively coupled plasma source for flat panel display processing

    NASA Astrophysics Data System (ADS)

    Lim, Jong Hyeuk; Kim, Kyong Nam; Park, Jung Kyun; Lim, Jong Tae; Yeom, Geun Young

    2008-02-01

    The variation in plasma uniformity over an extremely large size inductively coupled plasma (ICP) source of 2750×2350mm2 was examined. An internal linear-type antenna called "double comb-type antenna" was used as the ICP source. A plasma density of ˜1.4×1011/cm3 could be obtained at 5mTorr Ar by applying 10kW rf power to the source at a frequency of 13.56MHz. An increase in rf power from 1to10kW improved the plasma uniformity over a substrate area of 2300×2000mm2 from 18.1% to 11.4%. The improvement in uniformity of the internal ICP source was attributed to the increase in plasma density near the wall.

  6. Induction plasma tube

    DOEpatents

    Hull, D.E.

    1982-07-02

    An induction plasma tube having a segmented, fluid-cooled internal radiation shield is disclosed. The individual segments are thick in cross-section such that the shield occupies a substantial fraction of the internal volume of the plasma enclosure, resulting in improved performance and higher sustainable plasma temperatures. The individual segments of the shield are preferably cooled by means of a counterflow fluid cooling system wherein each segment includes a central bore and a fluid supply tube extending into the bore. The counterflow cooling system results in improved cooling of the individual segments and also permits use of relatively larger shield segments which permit improved electromagnetic coupling between the induction coil and a plasma located inside the shield. Four embodiments of the invention, each having particular advantages, are disclosed.

  7. Induction plasma tube

    DOEpatents

    Hull, Donald E.

    1984-01-01

    An induction plasma tube having a segmented, fluid-cooled internal radiation shield is disclosed. The individual segments are thick in cross-section such that the shield occupies a substantial fraction of the internal volume of the plasma enclosure, resulting in improved performance and higher sustainable plasma temperatures. The individual segments of the shield are preferably cooled by means of a counterflow fluid cooling system wherein each segment includes a central bore and a fluid supply tube extending into the bore. The counterflow cooling system results in improved cooling of the individual segments and also permits use of relatively larger shield segments which permit improved electromagnetic coupling between the induction coil and a plasma located inside the shield. Four embodiments of the invention, each having particular advantages, are disclosed.

  8. Induction plasma tube

    SciTech Connect

    Hull, D.E.

    1984-02-14

    An induction plasma tube having a segmented, fluid-cooled internal radiation shield is disclosed. The individual segments are thick in cross-section such that the shield occupies a substantial fraction of the internal volume of the plasma enclosure, resulting in improved performance and higher sustainable plasma temperatures. The individual segments of the shield are preferably cooled by means of a counterflow fluid cooling system wherein each segment includes a central bore and a fluid supply tube extending into the bore. The counterflow cooling system results in improved cooling of the individual segments and also permits use of relatively larger shield segments which permit improved electromagnetic coupling between the induction coil and a plasma located inside the shield. Four embodiments of the invention, each having particular advantages, are disclosed.

  9. Reduced electron temperature in a magnetized inductively-coupled plasma with internal coil

    SciTech Connect

    Arancibia Monreal, J.; Chabert, P.; Godyak, V.

    2013-10-15

    The effect of magnetic filtering on the electron energy distribution function is studied in an inductive discharge with internal coil coupling. The coil is placed inside the plasma and driven by a low-frequency power supply (5.8 MHz) which leads to a very high power transfer efficiency. A permanent dipole magnet may be placed inside the internal coil to produce a static magnetic field around 100 Gauss. The coil and the matching system are designed to minimize the capacitive coupling to the plasma. Capacitive coupling is quantified by measuring the radiofrequency (rf) plasma potential with a capacitive probe. Without the permanent magnet, the rf plasma potential is significantly smaller than the electron temperature. When the magnet is present, the rf plasma potential increases. The electron energy distribution function is measured as a function of space with and without the permanent magnet. When the magnet is present, electrons are cooled down to low temperature in the downstream region. This region of low electron temperature may be useful for plasma processing applications, as well as for efficient negative ion production.

  10. Nickel atom and ion densities in an inductively coupled plasma with an internal coil

    NASA Astrophysics Data System (ADS)

    Xu, Lin; Sadeghi, Nader; Donnelly, Vincent M.; Economou, Demetre J.

    2007-01-01

    The nickel atom density was measured in an inductively coupled argon plasma with an internal Ni coil, as a function of pressure and power, using optical absorption spectroscopy. Nickel atoms were sputtered from the coil and from a separate Ni target under optional target bias. A fraction of the atoms was ionized in the high-density plasma. The gas temperature was determined by analyzing the rovibrational spectra of the second positive system of nitrogen actinometer gas. The electron density was determined by optical emission spectroscopy in combination with a global model. For a pressure of 8-20mTorr and coil power of 40-200W, the Ni atom density ranged from 2.7×109to1.5×1010cm-3, increasing strongly with pressure. The Ni atom density first increased with power but saturated at high power levels. The measured Ni atom density agreed fairly well with the predictions of a global model, in particular, at the higher pressures. The model also predicted that the Ni+ ion density greatly increased at higher powers and pressures. Applying 70W bias on the target electrode increased the Ni atom density by 60%.

  11. Inductively coupled helium plasma torch

    SciTech Connect

    Montaser, Akbar; Chan, Shi-Kit; Van Hoven, Raymond L.

    1989-01-01

    An inductively coupled plasma torch including a base member, a plasma tube and a threaded insert member within the plasma tube for directing the plasma gas in a tangential flow pattern. The design of the torch eliminates the need for a separate coolant gas tube. The torch can be readily assembled and disassembled with a high degree of alignment accuracy.

  12. Closed inductively coupled plasma cell

    DOEpatents

    Manning, T.J.; Palmer, B.A.; Hof, D.E.

    1990-11-06

    A closed inductively coupled plasma cell generates a relatively high power, low noise plasma for use in spectroscopic studies is disclosed. A variety of gases can be selected to form the plasma to minimize spectroscopic interference and to provide a electron density and temperature range for the sample to be analyzed. Grounded conductors are placed at the tube ends and axially displaced from the inductive coil, whereby the resulting electromagnetic field acts to elongate the plasma in the tube. Sample materials can be injected in the plasma to be excited for spectroscopy. 1 fig.

  13. Closed inductively coupled plasma cell

    DOEpatents

    Manning, Thomas J.; Palmer, Byron A.; Hof, Douglas E.

    1990-01-01

    A closed inductively coupled plasma cell generates a relatively high power, low noise plasma for use in spectroscopic studies. A variety of gases can be selected to form the plasma to minimize spectroscopic interference and to provide a electron density and temperature range for the sample to be analyzed. Grounded conductors are placed at the tube ends and axially displaced from the inductive coil, whereby the resulting electromagnetic field acts to elongate the plasma in the tube. Sample materials can be injected in the plasma to be excited for spectroscopy.

  14. Ferromagnetic enhanced inductive plasma sources

    NASA Astrophysics Data System (ADS)

    Godyak, Valery

    2013-07-01

    The subject of this paper is the review of inductively coupled plasma (ICP) sources enhanced with ferromagnetic cores, FMICP, found in various applications, including plasma fusion, space propulsion, light sources, plasma chemistry and plasma processing of materials. The history of FMICP, early attempts for their realization, some recent developments and examples of successful FMICP devices are given here. A comparative study of FMICPs with conventional ICPs demonstrates their certain advantages in power transfer efficiency, power factor and their ability to operate without rf plasma potentials at low plasma densities and with small gaps, while effectively controlling plasma density profile.

  15. Starter for inductively coupled plasma tube

    DOEpatents

    Hull, D.E.; Bieniewski, T.M.

    1988-08-23

    A starter assembly is provided for use with an inductively coupled plasma (ICP) tube to reliably initiate a plasma at internal pressures above about 30 microns. A conductive probe is inserted within the inductor coil about the tube and insulated from the tube shield assembly. A capacitive circuit is arranged for momentarily connecting a high voltage radio-frequency generator to the probe while simultaneously energizing the coil. When the plasma is initiated the probe is disconnected from the generator and electrically connected to the shield assembly for operation. 1 fig.

  16. Starter for inductively coupled plasma tube

    DOEpatents

    Hull, Donald E.; Bieniewski, Thomas M.

    1988-01-01

    A starter assembly is provided for use with an inductively coupled plasma (ICP) tube to reliably initate a plasma at internal pressures above about 30 microns. A conductive probe is inserted within the inductor coil about the tube and insulated from the tube shield assembly. A capacitive circuit is arranged for momentarily connecting a high voltage radio-frequency generator to the probe while simultaneously energizing the coil. When the plasma is initiated the probe is disconnected from the generator and electrically connected to the shield assembly for operation.

  17. Mobile inductively coupled plasma system

    DOEpatents

    D`Silva, A.P.; Jaselskis, E.J.

    1999-03-30

    A system is described for sampling and analyzing a material located at a hazardous site. A laser located remotely from the hazardous site is connected to an optical fiber, which directs laser radiation proximate the material at the hazardous site. The laser radiation abates a sample of the material. An inductively coupled plasma is located remotely from the material. An aerosol transport system carries the ablated particles to a plasma, where they are dissociated, atomized and excited to provide characteristic optical reduction of the elemental constituents of the sample. An optical spectrometer is located remotely from the site. A second optical fiber is connected to the optical spectrometer at one end and the plasma source at the other end to carry the optical radiation from the plasma source to the spectrometer. 10 figs.

  18. Induction plasma spraying of ceramics

    NASA Astrophysics Data System (ADS)

    Fan, Xiao-Bao; Gougeon, Patrick; Gitzhofer, Francois; Boulos, Maher

    A study is carried out on the influence of in-flight particle parameters on their splatting properties during the induction plasma deposition of ceramics. Results are presented for alumina powders with mean particle diameters of 21 microns and 82 microns under soft vacuum conditions. The chamber pressure was varied between 46.6 and 66.6 kPa. Measurements are carried out on the particle surface temperature and velocity prior to impact on stainless steel substrates. The form of the splat obtained is evaluated using SEM. The results are used for the parametric optimization of the induction plasma spraying process. Thick alumina coatings with total porosities as low as 2 percent were obtained.

  19. Laser ablation inductively coupled plasma mass spectrometry

    SciTech Connect

    Durrant, S.F.

    1996-07-01

    Laser ablation for solid sample introduction to inductively coupled plasma mass spectrometry for bulk and spatially-resolved elemental analysis is briefly reviewed. {copyright} {ital 1996 American Institute of Physics.}

  20. Study on the heavy metal bioconcentrations of the Shadegan international wetland mosquitofish, Gambusia affinis, by inductively coupled plasma technique

    PubMed Central

    2013-01-01

    The purpose of this study was to evaluate the levels of heavy metal bioconcentration of the mosquitofish (Gambusia affinis) in Shadegan international wetland. Sampling including the water, waterbed sediment and mosquitofish was carried out from the selected sampling sites during October and November 2011, and analyzed by the ICP-OES. Results show that the water has poor qualitative condition, according to EPA and WHO water quality standards. The level of the water Cr in the selected sites in both months and the levels of Fe, Mn and Zn during October in the SW1 site were higher than the instrumental detection limits indicating that the water was contaminated with these metals in the mentioned sites and months. The levels of the waterbed sediment As, Co, Cr, Cu, Fe, Mn, Pb and Zn, and mosquitofish Cr, Cu, Fe, Mn, Zn, Co and Cd were much higher than the instrumental detection limits, indicating that the waterbed sediment and mosquitofish were contaminated with them during October and November in the selected sites. Statistical assessments reveal that there is a significant difference between the mentioned contaminated water, waterbed sediment and mosquitofish heavy metals (all P-values < 0.05). In overall, it is considered that the contaminated heavy metals can be accumulated in the waterbed sediment and bioconcentrated in the wildlife tissues, then finally can be entered in the marine food chains and biomagnified there after long periods. In conclusion, this paper confirmed that the G. affinis can be used as a bioindicator of heavy metal pollution in marine ecosystems such as wetlands. PMID:24499681

  1. Inductive coupled radio frequency plasma bridge neutralizer.

    PubMed

    Scholze, F; Tartz, M; Neumann, H

    2008-02-01

    A 13.56 MHz radio frequency plasma bridge neutralizer (rf-PBN) for ion thruster applications as well as ion beam surface processing of insulating materials is presented. The energy for the plasma excitation is inductively coupled into the plasma chamber. Because no components are located inside the plasma, the lifetime of the rf-PBN is expected to be very long. A compact tuning system adapts the input power to the plasma impedance. The electron current may be controlled over a wide range by the rf input power. An electron current of up to 1.6 A has been extracted. PMID:18315215

  2. Inductively generated streaming plasma ion source

    DOEpatents

    Glidden, Steven C.; Sanders, Howard D.; Greenly, John B.

    2006-07-25

    A novel pulsed, neutralized ion beam source is provided. The source uses pulsed inductive breakdown of neutral gas, and magnetic acceleration and control of the resulting plasma, to form a beam. The beam supplies ions for applications requiring excellent control of ion species, low remittance, high current density, and spatial uniformity.

  3. Pulsed Inductive Plasma Acceleration: Performance Optimization Criteria

    NASA Technical Reports Server (NTRS)

    Polzin, Kurt A.

    2014-01-01

    Optimization criteria for pulsed inductive plasma acceleration are developed using an acceleration model consisting of a set of coupled circuit equations describing the time-varying current in the thruster and a one-dimensional momentum equation. The model is nondimensionalized, resulting in the identification of several scaling parameters that are varied to optimize the performance of the thruster. The analysis reveals the benefits of underdamped current waveforms and leads to a performance optimization criterion that requires the matching of the natural period of the discharge and the acceleration timescale imposed by the inertia of the working gas. In addition, the performance increases when a greater fraction of the propellant is initially located nearer to the inductive acceleration coil. While the dimensionless model uses a constant temperature formulation in calculating performance, the scaling parameters that yield the optimum performance are shown to be relatively invariant if a self-consistent description of energy in the plasma is instead used.

  4. Characteristics of Plasma Using a Ferromagnetic Enhanced Inductively Coupled Plasma Source

    NASA Astrophysics Data System (ADS)

    Kim, Kyong Nam; Hyeuk Lim, Jong; Park, Jung Kyun; Lim, Jong Tae; Yeom, Geun Young

    2008-09-01

    Plasma characteristics and electrical parameters of an internal linear inductively coupled plasma (ICP) source with a U-type antenna with/without a Ni-Zn ferromagnetic material installed near the antenna were investigated. The application of the ferromagnetic material to the antenna increased the plasma density, improved the plasma uniformity, lowered the antenna voltage, and increased the stability of the plasma during the operation. For the U-type ferromagnetic enhanced internal linear ICP source, a high density plasma on the order of 4.5×1011 cm-3 which is about three higher than that obtained for the source without the ferromagnetic material could be obtained at the pressure of 10 mTorr Ar and at the RF power of 600 W at 13.56 MHz.

  5. Effects of internal inductance on the energy confinement time by using the solution of equilibrium problem

    NASA Astrophysics Data System (ADS)

    Asif, M.

    2016-06-01

    In this work, dependence of energy confinement time on plasma internal inductance has been studied by using the solution of Grad-Shafranov equation (GSE) for circular cross-section HT-7 tokamak. For this, the Shafranov parameter (asymmetry factor) and poloidal beta were obtained from solution of GSE. Then we can find the dependence of energy confinement time, on plasma internal inductance. It is observed that the maximum energy confinement time is related to the low values of internal inductance (0.7 < li < 0.9).

  6. Inductive Measurement of Plasma Jet Electrical Conductivity

    NASA Technical Reports Server (NTRS)

    Turner, Matthew W.; Hawk, Clark W.; Litchford, Ron J.

    2005-01-01

    An inductive probing scheme, originally developed for shock tube studies, has been adapted to measure explosive plasma jet conductivities. In this method, the perturbation of an applied magnetic field by a plasma jet induces a voltage in a search coil, which, in turn, can be used to infer electrical conductivity through the inversion of a Fredholm integral equation of the first kind. A 1-inch diameter probe was designed and constructed, and calibration was accomplished by firing an aluminum slug through the probe using a light-gas gun. Exploratory laboratory experiments were carried out using plasma jets expelled from 15-gram high explosive shaped charges. Measured conductivities were in the range of 3 kS/m for unseeded octol charges and 20 kS/m for seeded octol charges containing 2% potassium carbonate by mass.

  7. Electrical Coupling Efficiency of Inductive Plasma Accelerators

    NASA Technical Reports Server (NTRS)

    Martin, Adam K.; Eskridge, Richard H.

    2005-01-01

    A single-stage pulsed inductive plasma accelerator is modeled as an inductive mass-driver. The plasma is treated as a rigid slug, which acts as the armature. The system is a transformer, with the drive coil serving as the primary and the slug as the secondary. We derive a set of coupled dynamic-circuit equations, which depend on five dimensionless coefficients, and on the functional form of the mutual inductance profile, M (z). For a given coil geometry, M (z) was determined experimentally and compared to the results of calculations carried out with QuickField. The equations are solved with various coefficient values, in order to determine the conditions that yield high efficiencies. It was found that the coupling efficiency can be quite high and likely scales with power, although this does not preclude operation at lower power with acceptable efficiency. The effect of an imbedded magnetic bias flux, as for the case of a plasmoid thruster, was also included in the calculations.

  8. Building and analyzing models from data by stirred tank experiments for investigation of matrix effects caused by inorganic matrices and selection of internal standards in Inductively Coupled Plasma-Atomic Emission Spectroscopy

    NASA Astrophysics Data System (ADS)

    Grotti, Marco; Paredes, Eduardo; Maestre, Salvador; Todolí, José Luis

    2008-05-01

    Interfering effects caused by inorganic matrices (inorganic acids as well as easily ionized elements) in inductively coupled plasma-atomic emission spectroscopy have been modeled by regression analysis of experimental data obtained using the "stirred tank method". The main components of the experimental set-up were a magnetically-stirred container and two peristaltic pumps. In this way the matrix composition was gradually and automatically varied, while the analyte concentration remained unchanged throughout the experiment. An inductively coupled plasma spectrometer with multichannel detection based on coupled charge device was used to simultaneously measure the emission signal at several wavelengths when the matrix concentration was modified. Up to 50 different concentrations were evaluated in a period of time of 10 min. Both single interfering species (nitric, hydrochloric and sulphuric acids, sodium and calcium) and different mixtures (aqua regia, sulfonitric mixture, sodium-calcium mixture and sodium-nitric acid mixture) were investigated. The dependence of the emission signal on acid concentration was well-fitted by logarithmic models. Conversely, for the easily ionized elements, 3-order polynomial models were more suitable to describe the trends. Then, the coefficients of these models were used as "signatures" of the matrix-related signal variations and analyzed by principal component analysis. Similarities and differences among the emission lines were highlighted and discussed, providing a new insight into the interference phenomena, mainly with regards to the combined effect of concomitants. The combination of the huge amount of data obtained by the stirred tank method in a short period of time and the speed of analysis of principal component analysis provided a judicious means for the selection of the optimal internal standard in inductively coupled plasma-atomic emission spectroscopy.

  9. Plasma instabilities in electronegative inductive discharges

    NASA Astrophysics Data System (ADS)

    Marakhtanov, Alexei Mikhail

    Plasma instabilities have been observed in low-pressure inductive discharges, in the transition between low density capacitive mode and high density inductive mode of the discharge when attaching gases such as SF6 and Ar/SF 6 mixtures are used. Oscillations of charged particles, plasma potential and light emitted from the plasma with the frequencies from a few hertz to tens of kilohertz are seen for gas pressures between 1 and 100 mTorr and the discharge power in the range of 75--1200 W. The region of instability increases as the plasma becomes more electronegative and the frequency of plasma oscillations increases as the power, pressure, and gas flow rate increase. The instability frequencies may also depend on the settings of a matching network. A volume-averaged (global) model of the instability has been developed, for a discharge containing time varying densities of electrons, positive ions, and negative ions, and time invariant excited states and neutral densities. The particle and energy balance equations are integrated to produce the dynamical behavior. As pressure or power is varied to cross a threshold, the instability goes through a series of oscillatory states to large scale relaxation oscillations between higher and lower density states. The model qualitatively agrees with experimental observations, and also shows a significant influence of the matching network. A stability analysis of an electronegative discharge has been performed, using a Hurwitz criterion, for a system of linearized particle and power balance differential equations. Capacitive coupling plays a crucial role in the instability process. A variable electrostatic (Faraday) shield has been used to control the capacitive coupling from the excitation coil to the plasma. The plasma instability disappears when the shielded area exceeds 65% of the total area of the coil. The global model of instability gives a slightly higher value of 85% for instability suppression with the same discharge

  10. Line-type inductively coupled plasma source with ferromagnetic module

    NASA Astrophysics Data System (ADS)

    Hyeuk Lim, Jong; Kim, Kyong Nam; Gweon, Gwang Ho; Yeom, Geun Young

    2009-01-01

    The characteristics of a line-type, internal antenna for an inductively coupled plasma (ICP) source installed with a ferromagnetic module were investigated for possible application to roll-to-roll processing of next-generation display devices. The use of 2 MHz instead of 13.56 MHz for the 2300 mm long ICP source improved the plasma uniformity to less than 11% along the antenna line. In addition, the use of Ni-Zn ferromagnetic material in the line-type antenna improved the plasma density to about 3.1 × 1011 cm-3 at 3500 W of 2 MHz radio frequency power by confining the induced, time-varying magnetic field between the antenna line and the substrate. When the photoresist-covered glass substrate was etched at 4000 W using 40 mTorr and Ar/O2 (7 : 3), an etch uniformity of about 5-6% was obtained along the antenna line.

  11. Titanium oxidation by rf inductively coupled plasma

    NASA Astrophysics Data System (ADS)

    Valencia-Alvarado, R.; de la Piedad-Beneitez, A.; López-Callejas, R.; Barocio, S. R.; Mercado-Cabrera, A.; Peña-Eguiluz, R.; Muñoz-Castro, A. E.; Rodríguez-Méndez, B. G.; de la Rosa-Vázquez, J. M.

    2014-05-01

    The development of titanium dioxide (TiO2) films in the rutile and anatase phases is reported. The films have been obtained from an implantation/diffusion and sputtering process of commercially pure titanium targets, carried out in up to 500 W plasmas. The experimental outcome is of particular interest, in the case of anatase, for atmospheric pollution degradation by photocatalysis and, as to the rutile phase, for the production of biomaterials required by prosthesis and implants. The reactor employed consists in a cylindrical pyrex-like glass vessel inductively coupled to a 13.56 MHz RF source. The process takes place at a 5×10-2 mbar pressure with the target samples being biased from 0 to -3000 V DC. The anatase phase films were obtained from sputtering the titanium targets over glass and silicon electrically floated substrates placed 2 cm away from the target. The rutile phase was obtained by implantation/diffusion on targets at about 700 °C. The plasma was developed from a 4:1 argon/oxygen mixture for ~5 hour processing periods. The target temperature was controlled by means of the bias voltage and the plasma source power. The obtained anatase phases did not require annealing after the plasma oxidation process. The characterization of the film samples was conducted by means of x-ray diffraction, scanning electron microscopy, x-ray photoelectron spectroscopy and Raman spectroscopy.

  12. Method of processing materials using an inductively coupled plasma

    DOEpatents

    Hull, Donald E.; Bieniewski, Thomas M.

    1990-01-01

    A method for making fine power using an inductively coupled plasma. The method provides a gas-free environment, since the plasma is formed without using a gas. The starting material used in the method is in solid form.

  13. Thrust Stand Measurements of a Conical Pulsed Inductive Plasma Thruster

    NASA Technical Reports Server (NTRS)

    Hallock, Ashley K.; Polzin, Kurt A.; Emsellem, Gregory D.

    2012-01-01

    Pulsed inductive plasma thrusters [1-3] are spacecraft propulsion devices in which electrical energy is capacitively stored and then discharged through an inductive coil. The thruster is electrodeless, with a time-varying current in the coil interacting with a plasma covering the face of the coil to induce a plasma current. Propellant is accelerated and expelled at a high exhaust velocity (O(10-100 km/s)) by the Lorentz body force arising from the interaction of the magnetic field and the induced plasma current. While this class of thruster mitigates the life-limiting issues associated with electrode erosion, pulsed inductive plasma thrusters can su er from both high pulse energy requirements imposed by the voltage demands of inductive propellant ionization, and low propellant utilization efficiencies. The Microwave Assisted Discharge Inductive Plasma Accelerator (MAD-IPA)[4], shown in Fig. 1 is a pulsed inductive plasma thruster that is able to operate at lower pulse energies by partially ionizing propellant with an electron cyclotron resonance (ECR) discharge inside a conical inductive coil whose geometry serves to potentially increase propellant and plasma plume containment relative to at coil geometries. The ECR plasma is created with the use of permanent mag- nets arranged to produce a thin resonance region along the inner surface of the coil, restricting plasma formation and, in turn, current sheet formation to areas of high magnetic coupling to the driving coil.

  14. Laser Ablation Inductively Coupled Plasma Mass Spectrometry

    PubMed Central

    Hutchinson, Robert W.; McLachlin, Katherine M.; Riquelme, Paloma; Haarer, Jan; Broichhausen, Christiane; Ritter, Uwe; Geissler, Edward K.; Hutchinson, James A.

    2015-01-01

    ABSTRACT New analytical techniques for multiparametric characterisation of individual cells are likely to reveal important information about the heterogeneity of immunological responses at the single-cell level. In this proof-of-principle study, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was applied to the problem of concurrently detecting 24 lineage and activation markers expressed by human leucocytes. This approach was sufficiently sensitive and specific to identify subpopulations of isolated T, B, and natural killer cells. Leucocyte subsets were also accurately detected within unfractionated peripheral blood mononuclear cells preparations. Accordingly, we judge LA-ICP-MS to be a suitable method for assessing expression of multiple tissue antigens in solid-phase biological specimens, such as tissue sections, cytospins, or cells grown on slides. These results augur well for future development of LA-ICP-MS–based bioimaging instruments for general users. PMID:27500232

  15. Intelligent autonomous inductively coupled plasma instrumental operation

    NASA Astrophysics Data System (ADS)

    Webb, Douglas P.

    The development of a framework for the automated analysis of inductively couple plasma atomic emission spectroscopy is present. Some of the research that lead to current state of this framework is presented. A small expert system that uses information about the current sample to generate a line search strategy which minimizes the number of emission lines which need to be measured, and avoids spectral overlaps when possible. A program is presented that evaluates the minimum number of spectral windows required to perform elemental analysis by ICP- AES, given a certain spectral window width. A method with the potential for rapidly ascertaining the physical properties of the sample matrix is presented. This system has the potential to help reduce sample introduction related system failures. Finally, three optimization algorithms are compared in their ability to optimize ICP- AES performance, from this an optimization module was developed for inclusion in the automated analysis framework.

  16. Internal standardization for the determination of cadmium, cobalt, chromium and manganese in saline produced water from petroleum industry by inductively coupled plasma optical emission spectrometry after cloud point extraction

    NASA Astrophysics Data System (ADS)

    Bezerra, Marcos Almeida; Mitihiro do Nascimento Maêda, Sérgio; Oliveira, Eliane Padua; de Fátima Batista de Carvalho, Maria; Santelli, Ricardo Erthal

    2007-09-01

    In the present paper a procedure is proposed for the determination of traces of Cd, Co, Mn and Cr in petroleum industry produced water by inductively coupled plasma optical emission spectrometry. The procedure is based on cloud point extraction of these metals, as their dithizonate complexes, into the surfactant-rich phase of octylphenoxypolyethoxyethanol surfactant (Triton X-114). Extractions were carried out in solutions with salinities between 10‰ and 70‰. Since residual salinity in the surfactant-rich phase caused differences in its transport to the plasma, yttrium was used as an internal standard to correct for this effect. The simultaneous metal extraction procedure was optimized by response surface methodology using a Doehlert design and desirability function. Enhancement factors of 21, 21, 9 and 19, along with limits of quantification of 0.093, 0.20, 0.73 and 1.2 μg L - 1 , and precision expressed as relative standard deviation ( n = 8, 20.0 μg L - 1 ) of 5.8, 1.2, 1.7 and 5.7% were obtained for Cd, Co, Mn and Cr, respectively. The accuracy was evaluated by spike recovery tests on the high salinity water samples with salinity of 40 and 63‰.

  17. Design of a Microwave Assisted Discharge Inductive Plasma Accelerator

    NASA Technical Reports Server (NTRS)

    Hallock, Ashley K.; Polzin, Kurt A.

    2010-01-01

    A new plasma accelerator concept that employs electrodeless plasma preionization and pulsed inductive acceleration is presented. Preionization is achieved through an electron cyclotron resonance discharge that produces a weakly-ionized plasma at the face of a conical theta pinch-shaped inductive coil. The presence of the preionized plasma allows for current sheet formation at lower discharge voltages than those found in other pulsed inductive accelerators. The location of an electron cyclotron resonance discharge can be controlled through the design of the applied magnetic field in the thruster. A finite-element model of the magnetic field was used as a design tool, allowing for the implementation of an arrangement of permanent magnets that yields a small volume of preionized propellant at the coil face. This allows for current sheet formation at the face of the inductive coil, minimizing the initial inductance of the pulse circuit and maximizing the potential efficiency of the new accelerator.

  18. Thrust Stand Measurements of a Conical Inductive Pulsed Plasma Thruster

    NASA Technical Reports Server (NTRS)

    Hallock, Ashley K.; Polzin, Kurt A.

    2013-01-01

    Inductive Pulsed Plasma Thrusters (iPPT) spacecraft propulsion devices in which electrical energy is capacitively stored and then discharged through an inductive coil. The thruster is electrodeless, with a time-varying current in the coil interacting with a plasma covering the face of the coil to induce a plasma current Propellant is accelerated and expelled at a high exhaust velocity (O(10 -- 100 km/s)) by the Lorentz body force arising from the interaction of the magnetic field and the induced plasma current. While this class of thruster mitigates the life-limiting issues associated with electrode erosion, inductive pulsed plasma thrusters can suffer from both high pulse energy requirements imposed by the voltage demands of inductive propellant ionization, and low propellant utilization efficiencies. While this class of thruster mitigates the life-limiting issues associated with electrode erosion, inductive pulsed plasma thrusters can suffer from both high pulse energy requirements imposed by the voltage demands of inductive propellant ionization, and low propellant utilization efficiencies. A conical coil geometry may offer higher propellant utilization efficiency over that of a at inductive coil, however an increase in propellant utilization may be met with a decrease in axial electromagnetic acceleration, and in turn, a decrease in the total axially-directed kinetic energy imparted to the propellant.

  19. Transition of RF internal antenna plasma by gas control

    SciTech Connect

    Hamajima, Takafumi; Yamauchi, Toshihiko; Kobayashi, Seiji; Hiruta, Toshihito; Kanno, Yoshinori

    2012-07-11

    The transition between the capacitively coupled plasma (CCP) and the inductively coupled plasma (ICP) was investigated with the internal radio frequency (RF) multi-turn antenna. The transition between them showed the hysteresis curve. The radiation power and the period of the self-pulse mode became small in proportion to the gas pressure. It was found that the ICP transition occurred by decreasing the gas pressure from 400 Pa.

  20. EVALUATION OF AN INDUCTIVELY COUPLED PLASMA, MULTICHANNEL SPECTROMETRIC ANALYSIS SYSTEM

    EPA Science Inventory

    An inductively coupled plasma, multielement atomic emission spectrometric analysis system has been evaluated with respect to the Environmental Protection Agency's need for a rapid method for determination of trace elemental concentrations in water. Data are presented on detection...

  1. Method of processing materials using an inductively coupled plasma

    DOEpatents

    Hull, Donald E.; Bieniewski, Thomas M.

    1989-01-01

    A method for coating surfaces or implanting ions in an object using an inductively coupled plasma. The method provides a gas-free environment, since the plasma is formed without using a gas. The coating material or implantation material is intitially in solid form.

  2. Information Architecture without Internal Theory: An Inductive Design Process.

    ERIC Educational Resources Information Center

    Haverty, Marsha

    2002-01-01

    Suggests that information architecture design is primarily an inductive process, partly because it lacks internal theory and partly because it is an activity that supports emergent phenomena (user experiences) from basic design components. Suggests a resemblance to Constructive Induction, a design process that locates the best representational…

  3. Ion-wave stabilization of an inductively coupled plasma

    SciTech Connect

    Camparo, J.C.; Mackay, R.

    2006-04-24

    Stabilization of the rf power driving an inductively coupled plasma (ICP) has implications for fields ranging from atomic clocks to analytical chemistry to illumination technology. Here, we demonstrate a technique in which the plasma itself acts as a probe of radio wave power, and provides a correction signal for active rf-power control. Our technique takes advantage of the resonant nature of forced ion waves in the plasma, and their observation in the ICP's optical emission.

  4. Inductively coupled plasma etching of GaN

    SciTech Connect

    Shul, R.J.; McClellan, G.B.; Casalnuovo, S.A.; Rieger, D.J.; Pearton, S.J.; Constantine, C.; Barratt, C.; Karlicek, R.F. Jr.; Tran, C.; Schurman, M.

    1996-08-01

    Inductively coupled plasma (ICP) etch rates for GaN are reported as a function of plasma pressure, plasma chemistry, rf power, and ICP power. Using a Cl{sub 2}/H{sub 2}/Ar plasma chemistry, GaN etch rates as high as 6875 A/min are reported. The GaN surface morphology remains smooth over a wide range of plasma conditions as quantified using atomic force microscopy. Several etch conditions yield highly anisotropic profiles with smooth sidewalls. These results have direct application to the fabrication of group-III nitride etched laser facets. {copyright} {ital 1996 American Institute of Physics.}

  5. Thrust Stand Measurements of a Conical Inductive Pulsed Plasma Thruster

    NASA Technical Reports Server (NTRS)

    Hallock, Ashley K.; Polzin, Kurt A.

    2012-01-01

    Inductive Pulsed Plasma Thrusters (iPPT) are spacecraft propulsion devices in which electrical energy is capacitively stored and then discharged through an inductive coil. The thruster is electrodeless, with a time-varying current in the coil interacting with a plasma covering the face of the coil to induce a plasma current. Propellant is accelerated and expelled at a high exhaust velocity (O(10 .. 100 km/s)) by the Lorentz body force arising from the interaction of the magnetic field and the induced plasma current. While this class of thruster mitigates the life-limiting issues associated with electrode erosion, inductive pulsed plasma thrusters can suffer from both high pulse energy requirements imposed by the voltage demands of inductive propellant ionization, and low propellant utilization efficiencies. A conical coil geometry may o er higher propellant utilization efficiency over that of a at inductive coil, however an increase in propellant utilization may be met with a decrease in axial electromagnetic acceleration, and in turn, a decrease in the total axially-directed kinetic energy imparted to the propellant.

  6. Exemplary Teacher Induction: An International Review

    ERIC Educational Resources Information Center

    Howe, Edward R.

    2006-01-01

    How does one become an effective teacher? What can be done to stem high attrition rates among beginning teachers? While many teachers are left to "sink or swim" in their first year--learning by trial and error, there remain a number of outstanding examples of collaboration and collegiality in teacher induction programs. Analysis of the most…

  7. Plasma igniter for internal-combustion engines

    NASA Technical Reports Server (NTRS)

    Breshears, R. R.; Fitzgerald, D. J.

    1978-01-01

    Hot ionized gas (plasma) ignites air/fuel mixture in internal combustion engines more effectively than spark. Electromagnetic forces propel plasma into combustion zone. Combustion rate is not limited by flame-front speed.

  8. International movement of plasma and plasma contracting.

    PubMed

    Farrugia, A

    2005-01-01

    Plasma fractionation is a global business characterised by technological stability, increasing consolidation and a high level of regulatory oversight. All these factors affect the ease with which plasma derivatives can be accessed in the world market. As domestic regulatory measures in the first world blood economies become increasingly resonant to the precautionary approach, the availability of plasma as a raw material, as well as its cost, become an increasingly significant component in the cost of the final product. This decreases the amount of plasma which fractionators are able to allocate for export activities. Also, regulatory standards in the country of manufacture will reflect priorities in that country which may not be similar to those in export markets, but which will affect entry to those markets. While many countries possess a fractionation capacity, the limiting factor in supply worldwide is the amount of plasma available, and nationalistic drivers for each country to have its own plant are inimical to product safety and supply. Rather, the provision of sufficient supplies of domestic plasma should be the focus of resource allocation, with a choice of an appropriate contract fractionator. However, contract fractionation too may be affected by domestic considerations unrelated to the needs of the country of plasma origin. This chapter will review the global plasma market and the influences on plasma and plasma product movement across national borders. Problems in ensuring adequate safety and supply will be identified, and some tentative approaches to the amelioration of current barriers to the provision of plasma derivatives will be outlined. PMID:16050160

  9. Design of a Microwave Assisted Discharge Inductive Plasma Accelerator

    NASA Technical Reports Server (NTRS)

    Hallock, Ashley K.; Polzin, Kurt A.

    2010-01-01

    The design and construction of a thruster that employs electrodeless plasma preionization and pulsed inductive acceleration is described. Preionization is achieved through an electron cyclotron resonance discharge that produces a weakly-ionized plasma at the face of a conical theta pinch-shaped inductive coil. The presence of the preionized plasma allows for current sheet formation at lower discharge voltages than those employed in other pulsed inductive accelerators that do not employ preionization. The location of the electron cyclotron resonance discharge is controlled through the design of the applied magnetic field in the thruster. Finite element analysis shows that there is an arrangement of permanent magnets that yields a small volume of resonant magnetic field at the coil face. Preionization in the resonant zone leads to current sheet formation at the coil face, which minimizes the initial inductance of the pulse circuit and maximizes the potential electrical efficiency of the accelerator. A magnet assembly was constructed around an inductive coil to provide structural support to the selected arrangement of neodymium magnets. Measured values of the resulting magnetic field compare favorably with the finite element model.

  10. Advances in induction-heated plasma torch technology

    NASA Technical Reports Server (NTRS)

    Poole, J. W.; Vogel, C. E.

    1972-01-01

    Continuing research has resulted in significant advances in induction-heated plasma torch technology which extend and enhance its potential for broad range of uses in chemical processing, materials development and testing, and development of large illumination sources. Summaries of these advances are briefly described.

  11. Method of processing materials using an inductively coupled plasma

    DOEpatents

    Hull, D.E.; Bieniewski, T.M.

    1987-04-13

    A method of processing materials. The invention enables ultrafine, ultrapure powders to be formed from solid ingots in a gas free environment. A plasma is formed directly from an ingot which insures purity. The vaporized material is expanded through a nozzle and the resultant powder settles on a cold surface. An inductively coupled plasma may also be used to process waste chemicals. Noxious chemicals are directed through a series of plasma tubes, breaking molecular bonds and resulting in relatively harmless atomic constituents. 3 figs.

  12. Inductively coupled plasma torch with laminar flow cooling

    DOEpatents

    Rayson, Gary D.; Shen, Yang

    1991-04-30

    An improved inductively coupled gas plasma torch. The torch includes inner and outer quartz sleeves and tubular insert snugly fitted between the sleeves. The insert includes outwardly opening longitudinal channels. Gas flowing through the channels of the insert emerges in a laminar flow along the inside surface of the outer sleeve, in the zone of plasma heating. The laminar flow cools the outer sleeve and enables the torch to operate at lower electrical power and gas consumption levels additionally, the laminar flow reduces noise levels in spectroscopic measurements of the gaseous plasma.

  13. Resonant planar antenna as an inductive plasma source

    SciTech Connect

    Guittienne, Ph.; Lecoultre, S.; Howling, A. A.; Hollenstein, Ch.; Fayet, P.; Larrieu, J.

    2012-04-15

    A resonant planar antenna as an inductive plasma source operating at 13.56 MHz inside a low pressure vacuum vessel is presented for potential plasma processing applications. Its principle consists in interconnecting elementary resonant meshes composed of inductive and capacitive elements. Due to its structure, the antenna shows a set of resonant modes associated with peaks of the real input impedance. Each of these modes is defined by its own current and voltage distribution oscillating at the frequency of the mode. A rectangular antenna of 0.55mx0.20m has been built, and first results obtained with argon plasmas are presented. Plasma generation is shown to be efficient as densities up to 4{center_dot}10{sup 17}m{sup -3} at 2000 W have been measured by microwave interferometry at a distance of 4 cm from the source plane. It is also demonstrated that the plasma couples inductively with the resonating currents flowing in the antenna above a threshold power of about 60 W. A non-uniformity of less than {+-}5% is obtained at 1000 W at a few centimeters above the antenna over 75% of its surface.

  14. A new continuous calibration method for inductively coupled plasma spectrometry.

    PubMed

    Paredes, E; Maestre, S E; Todolí, J L

    2006-01-01

    A new calibration method was developed and applied to inductively coupled plasma atomic emission spectrometry. External calibration was performed as follows. A container was filled with a given volume of deionized (V(p)) water. Then a concentrated standard was introduced at a controlled rate (Q(e)) into the tank by means of a peristaltic pump. The resulting solution was stirred throughout the experiment. Simultaneously, the solution inside the tank was pumped from the vessel to the plasma at a given rate (Q(s)). The signal was continuously recorded. The variation of the concentration of the solution leaving the tank with time was determined by applying a basic equation of stirred tanks. The representation of the emission intensity versus the time and the further conversion of the time scale into a concentration scale gave rise to the calibration line. The best results in terms of linearity were achieved for V(p)=15 cm3, Q(e)=0.6-0.75 ml min(-1) and Q(s)=1-1.2 ml min(-1). Graphs with more than 40 standards were obtained within about 10 min. The results found were not statistically different from those afforded by the conventional calibration method. In addition, the new method was faster and supplied better linearity and precision than the conventional one. Another advantage of the stirred tank was that procedures such as dynamic calibration and standard additions could be easily and quickly applied, thus shortening the analysis time. A complete analysis following these procedures based on the measurement of 30 standards took about 5 min. Several synthetic as well as certified samples (i.e., bovine liver, mussel tissue and powdered milk) were analyzed with the stirred tank by applying four different calibration methodologies (i.e., external calibration, internal calibration, standard additions and a combination of internal standardization and standard additions), with the combination of internal standardization and standard additions being the method that provided

  15. Vacuum arc plasma thrusters with inductive energy storage driver

    NASA Technical Reports Server (NTRS)

    Schein, Jochen (Inventor); Gerhan, Andrew N. (Inventor); Woo, Robyn L. (Inventor); Au, Michael Y. (Inventor); Krishnan, Mahadevan (Inventor)

    2004-01-01

    An apparatus for producing a vacuum arc plasma source device using a low mass, compact inductive energy storage circuit powered by a low voltage DC supply acts as a vacuum arc plasma thruster. An inductor is charged through a switch, subsequently the switch is opened and a voltage spike of Ldi/dt is produced initiating plasma across a resistive path separating anode and cathode. The plasma is subsequently maintained by energy stored in the inductor. Plasma is produced from cathode material, which allows for any electrically conductive material to be used. A planar structure, a tubular structure, and a coaxial structure allow for consumption of cathode material feed and thereby long lifetime of the thruster for long durations of time.

  16. Impact of Gas Heating in Inductively Coupled Plasmas

    NASA Technical Reports Server (NTRS)

    Hash, D. B.; Bose, D.; Rao, M. V. V. S.; Cruden, B. A.; Meyyappan, M.; Sharma, S. P.; Biegel, Bryan (Technical Monitor)

    2001-01-01

    Recently it has been recognized that the neutral gas in inductively coupled plasma reactors heats up significantly during processing. The resulting gas density variations across the reactor affect reaction rates, radical densities, plasma characteristics, and uniformity within the reactor. A self-consistent model that couples the plasma generation and transport to the gas flow and heating has been developed and used to study CF4 discharges. A Langmuir probe has been used to measure radial profiles of electron density and temperature. The model predictions agree well with the experimental results. As a result of these comparisons along with the poorer performance of the model without the gas-plasma coupling, the importance of gas heating in plasma processing has been verified.

  17. Inductive and Electrostatic Acceleration in Relativistic Jet-Plasma Interactions

    SciTech Connect

    Ng, Johnny S.T.; Noble, Robert J.; /SLAC

    2005-07-13

    We report on the observation of rapid particle acceleration in numerical simulations of relativistic jet-plasma interactions and discuss the underlying mechanisms. The dynamics of a charge-neutral, narrow, electron-positron jet propagating through an unmagnetized electron-ion plasma was investigated using a three-dimensional, electromagnetic, particle-in-cell computer code. The interaction excited magnetic filamentation as well as electrostatic (longitudinal) plasma instabilities. In some cases, the longitudinal electric fields generated inductively and electrostatically reached the cold plasma wave-breaking limit, and the longitudinal momentum of about half the positrons increased by 50% with a maximum gain exceeding a factor of two. The results are relevant to understanding the micro-physics at the interface region of an astrophysical jet with the interstellar plasma, for example, the edge of a wide jet or the jet-termination point.

  18. Plasma Interaction and Induction Signatures at Callisto: Preparations for JUICE

    NASA Astrophysics Data System (ADS)

    Liuzzo, Lucas; Feyerabend, Moritz; Simon, Sven; Motschmann, Uwe

    2016-04-01

    The interaction of the Jovian magnetospheric environment with an atmosphere and induced dipole at Callisto is investigated by applying a hybrid (kinetic ions, fluid electrons) simulation code. Callisto is unique among the Galilean satellites in its interaction with the ambient magnetospheric plasma as the gyroradii of the impinging plasma and pickup ions are large compared to the size of the moon. A kinetic representation of the ions is therefore mandatory to adequately describe the resulting asymmetries in the electromagnetic fields and the deflection of the plasma flow near Callisto. When Callisto is embedded in the magnetodisk lobes of Jupiter, a dipolar magnetic field is generated via induction in a subsurface ocean. This field creates an obstacle to the impinging magnetospheric plasma flow at the moon. However, when Callisto is located near the center of the Jovian current sheet, local magnetic perturbations due to the magnetosphere-ionosphere interaction are more than twice the strength of the background field and may therefore obscure any magnetic signal generated via induction in a subsurface ocean. Our simulations demonstrate that the deflection of the magnetospheric plasma into Callisto's wake cannot alone explain the plasma density enhancement of two orders of magnitude measured in the wake of the interaction region during Galileo flybys of the moon. However, through inclusion of an ionosphere around Callisto, modeled densities in the wake are consistent with in situ measurements.

  19. Electron energy distributions in a magnetized inductively coupled plasma

    SciTech Connect

    Song, Sang-Heon E-mail: Sang-Heon.Song@us.tel.com; Yang, Yang; Kushner, Mark J.

    2014-09-15

    Optimizing and controlling electron energy distributions (EEDs) is a continuing goal in plasma materials processing as EEDs determine the rate coefficients for electron impact processes. There are many strategies to customize EEDs in low pressure inductively coupled plasmas (ICPs), for example, pulsing and choice of frequency, to produce the desired plasma properties. Recent experiments have shown that EEDs in low pressure ICPs can be manipulated through the use of static magnetic fields of sufficient magnitudes to magnetize the electrons and confine them to the electromagnetic skin depth. The EED is then a function of the local magnetic field as opposed to having non-local properties in the absence of the magnetic field. In this paper, EEDs in a magnetized inductively coupled plasma (mICP) sustained in Ar are discussed with results from a two-dimensional plasma hydrodynamics model. Results are compared with experimental measurements. We found that the character of the EED transitions from non-local to local with application of the static magnetic field. The reduction in cross-field mobility increases local electron heating in the skin depth and decreases the transport of these hot electrons to larger radii. The tail of the EED is therefore enhanced in the skin depth and depressed at large radii. Plasmas densities are non-monotonic with increasing pressure with the external magnetic field due to transitions between local and non-local kinetics.

  20. An analytic determination of beta poloidal and internal inductance in an elongated tokamak from magnetic probe measurements

    SciTech Connect

    Sorci, J.M.

    1992-02-01

    Analytic calculations of the magnetic fields available to magnetic diagnostics are performed for tokamaks with circular and elliptical cross sections. The explicit dependence of the magnetic fields on the poloidal beta and internal inductances is sought. For tokamaks with circular cross sections, Shafranov`s results are reproduced and extended. To first order in the inverse aspect ratio expansion of the magnetic fields, only a specific combination of beta poloidal and internal inductance is found to be measurable. To second order in the expansion, the measurements of beta poloidal and the internal inductance are demonstrated to be separable but excessively sensitive to experimental error. For tokamaks with elliptical cross sections, magnetic measurements are found to determine beta poloidal and the internal inductance separately. A second harmonic component of the zeroth order field in combination with the dc harmonic of the zeroth order field specifies the internal inductance. The internal inductance in hand, measurement of the first order, first harmonic component of the magnetic field then determined beta poloidal. The degeneracy implicit in Shafranov`s result (i.e. that only a combination of beta poloidal and internal inductance is measurable for a circular plasma cross section) reasserts itself as the elliptic results are collapsed to their circular limits.

  1. An analytic determination of beta poloidal and internal inductance in an elongated tokamak from magnetic probe measurements

    SciTech Connect

    Sorci, J.M.

    1992-02-01

    Analytic calculations of the magnetic fields available to magnetic diagnostics are performed for tokamaks with circular and elliptical cross sections. The explicit dependence of the magnetic fields on the poloidal beta and internal inductances is sought. For tokamaks with circular cross sections, Shafranov's results are reproduced and extended. To first order in the inverse aspect ratio expansion of the magnetic fields, only a specific combination of beta poloidal and internal inductance is found to be measurable. To second order in the expansion, the measurements of beta poloidal and the internal inductance are demonstrated to be separable but excessively sensitive to experimental error. For tokamaks with elliptical cross sections, magnetic measurements are found to determine beta poloidal and the internal inductance separately. A second harmonic component of the zeroth order field in combination with the dc harmonic of the zeroth order field specifies the internal inductance. The internal inductance in hand, measurement of the first order, first harmonic component of the magnetic field then determined beta poloidal. The degeneracy implicit in Shafranov's result (i.e. that only a combination of beta poloidal and internal inductance is measurable for a circular plasma cross section) reasserts itself as the elliptic results are collapsed to their circular limits.

  2. Technoeconomic analysis for the destruction of toxic liquid wastes using induction plasma technology

    SciTech Connect

    Soucy, G.; Bergeron, E.; Boulos, M.I.

    1995-12-31

    During the past decade, thermal plasma technology has been pointed out as one of the most promising innovative technologies for the thermal destruction of hazardous wastes and for this role, it has been supported by the EPA. In this field, many process alternatives have been developed but insufficient attention have been given to the details of their economic viability. The objective of this paper is to carry out an economic analysis of a particular thermal induction plasma technology for toxic liquid waste destruction. This work is presented in three parts. The first part presents a description of the conceptual design for a process using high frequency (HF) induction plasma. The second part, based on an order-of-magnitude factored estimate, provides an analysis of the capital investment cost of this process. The third part presents an estimation of the operating costs and a discounted cash flow analysis of this conceptual project using a HF plasma generator. The analysis of the economic viability is discussed with reference to the net present worth and the internal rate of return. The discussion examines those variables that significantly affect the viability of such technology by exploring its advantages towards minimizing impacts on the global environment and economic situation. Finally, a comparison is drawn up between the induction plasma technology and other alternative competitive processes.

  3. Improvement of uniformity in a weakly magnetized inductively coupled plasma

    NASA Astrophysics Data System (ADS)

    Lee, W. H.; Cheong, H. W.; Kim, J. W.; Whang, K. W.

    2015-12-01

    Magnetic fields are applied to inductively coupled plasma (ICP) to achieve high plasma densities using electromagnets. If the magnetic fields are set up such that the magnitude of magnetic flux density on the substrate decreases with both radial and axial distances from the substrate’s center (here after referred to as M-ICP-A), the plasma density increases by 237% compared with that for ICP although the non-uniformity of the plasma density for M-ICP-A (11.1%) is higher than that for ICP (10.9%). As the rate of decrease in the magnitude of magnetic flux density on the substrate increases both radially and axially, the non-uniformity in the plasma density increases further. The increase in the non-uniformity for M-ICP-A was confirmed to arise from the flute instability. To suppress the flute instability, we arranged the magnitude of magnetic flux density on the substrate to increase with increasing distance from the substrate center both radially and axially (here after referred to as M-ICP-V). In this configuration, plasma fluctuations were not observed, hence the plasma density non-uniformity was lowered to 8.1%, although the measured plasma density was higher than that for M-ICP-A. The oxide etch-rate non-uniformity in M-ICP-V (2.5%) was also lower than that for ICP (5.2%) or that for M-ICP-A (21.4%).

  4. AETHER: A simulation platform for inductively coupled plasma

    NASA Astrophysics Data System (ADS)

    Turkoz, Emre; Celik, Murat

    2015-04-01

    An in-house code is developed to simulate the inductively coupled plasma (ICP). The model comprises the fluid, electromagnetic and transformer submodels. Fluid equations are solved to evaluate the plasma flow parameters, including the plasma and neutral densities, ion and neutral velocities, electron flux, electron temperature, and electric potential. The model relies on the ambipolar approximation and offers the evaluation of plasma parameters without solving the sheath region. The electromagnetic model handles the calculation of the electric and magnetic fields using the magnetic vector potential. The transformer model captures the effect of the matching circuit utilized in laboratory experiments for RF power deposition. The continuity and momentum equations are solved using finite volume method. The energy, electric potential, and magnetic vector potential equations are solved using finite difference method. The resulting linear systems of equations are solved with iterative solvers including Jacobi and GMRES. The code is written using the C++ programming language, it works in parallel and has graphical user interface. The model is applied to study ICP characteristics of a plasma confined within a cylindrical chamber with dielectric walls for two different power deposition cases. The results obtained from the developed model are verified using the plasma module of COMSOL Multiphysics. The model is also applied to a plasma source configuration, and it is demonstrated that there is an overall increase in the plasma potential when current is extracted from ICP with a biased wall electrode.

  5. Characterization of an inductively coupled plasma source with convergent nozzle

    NASA Astrophysics Data System (ADS)

    Dropmann, Michael; Clements, Kathryn; Edgren, Josh; Laufer, Rene; Herdrich, Georg; Matthews, Lorin; Hyde, Truell

    2015-11-01

    The inductively heated plasma generator (IPG6-B) located in the CASPER labs at Baylor University has recently been characterized for both air, nitrogen and helium. A primary area of research within the intended scope of the instrument is the analysis of material degradation under high heat fluxes such as those imposed by a plasma during atmospheric entry of a spacecraft and at the divertor within various fusion experiment. In order to achieve higher flow velocities and respectively higher heat fluxes, a new exit flange has been designed to allow the installation of nozzles with varying geometries at the exit of the plasma generator. This paper will discuss characterization of the plasma generator for a convergent nozzle accelerating the plasma jet to supersonic velocity. The diagnostics employed include a cavity calorimeter to measure the total plasma power, a Pitot probe to measure stagnation pressure and a heat flux probe to measure the local heat flux. Radial profiles of stagnation pressure and heat flux allowing the determination of the local plasma enthalpy in the plasma jet will be presented. Support from the NSF and the DOE (award numbers PHY-1262031 and PHY-1414523) is gratefully acknowledged.

  6. Relatively high plasma density in low pressure inductive discharges

    SciTech Connect

    Kang, Hyun-Ju; Kim, Yu-Sin; Chung, Chin-Wook

    2015-09-15

    Electron energy probability functions (EEPFs) were measured in a low pressure argon inductive discharge. As radio frequency (RF) power increases, discharge mode is changed from E-mode (capacitively coupled) to H-mode (inductively coupled) and the EEPFs evolve from a bi-Maxwellian distribution to a Maxwellian distribution. It is found that the plasma densities at low RF powers (<30 W) are much higher than the density predicted from the slope of the densities at high powers. Because high portion of high energy electrons of the bi-Maxwellian distribution lowers the collisional energy loss and low electron temperature of low energy electrons reduces particle loss rate at low powers. Therefore, the energy loss of plasma decreases and electron densities become higher at low powers.

  7. Thin film coating process using an inductively coupled plasma

    DOEpatents

    Kniseley, Richard N.; Schmidt, Frederick A.; Merkle, Brian D.

    1990-01-30

    Thin coatings of normally solid materials are applied to target substrates using an inductively coupled plasma. Particles of the coating material are vaporized by plasma heating, and pass through an orifice to a first vacuum zone in which the particles are accelerated to a velocity greater than Mach 1. The shock wave generated in the first vacuum zone is intercepted by the tip of a skimmer cone that provides a second orifice. The particles pass through the second orifice into a second zone maintained at a higher vacuum and impinge on the target to form the coating. Ultrapure coatings can be formed.

  8. Simulation of Plasma Characteristics for Inductively Coupled Argon Plasma Using Dual-Frequency Antennas

    NASA Astrophysics Data System (ADS)

    Li, Xue-Chun; Sun, Xiao-Yan; Wang, You-Nian

    2014-10-01

    A large-area wafer size is necessary for plasma processing in the micro-electronics industry. However, it is one of the most important issues to obtain uniform plasma over a large-area substrate in addition to high-density plasmas for the plasma processing. Recently, the experimental study on the dual-frequency inductively coupled plasma (ICP) has been reported as a mean of improving the plasma uniformity over the large-area substrate. In this work, we develop a self-consistent method combined with the electromagnetic theory and fluid model to simulate the plasma characteristics for dual-frequency inductively coupled argon plasma. In the model, the ICP source consists of two planar-spiral coils. We investigate the plasma uniformity problem by adjusting the parameters of the two coils, such as the RF current, the position of the coils and the RF frequency ratio. It was found that the uniformity of the ion density over the wafer is improved with dual-frequency antennas comparing with a single-frequency antenna. The plasma uniformity increases when the coils are located farther from the centre of the ICP source. It is consistent with the experimental study. This work was supported by the National Natural Science Foundation of China (No. 11175034, No. 11075029).

  9. Effect of Inductive Coil Geometry on the Operating Characteristics of a Pulsed Inductive Plasma Accelerator

    NASA Astrophysics Data System (ADS)

    Hallock, Ashley Kristin

    The effect of inductive coil geometry on the operating characteristics of a pulsed inductive plasma thruster is investigated analytically and experimentally. Coil inductance is measured as a function of the position of a simulated current sheet and modeled using finite element analysis to develop a two-dimensional semi-empirical inductance relation that is used to expand a circuit-based acceleration model from one to two dimensions. The model includes electromagnetic and gas-dynamic forces but excludes any process to translate radial plasma motion into axial motion. Furthermore a magnetically-impermeable current sheet encompassing all the propellant for a pulse is assumed to form immediately at the start of the pulse and at the surface of the inductive coil. The two-dimensional acceleration model is nondimensionalized, yielding a set of dimensionless performance scaling parameters. Model results indicate that the introduction of radial current sheet motion caused by a conical inductive coil geometry (versus a flat circular plate) increases the axial dynamic impedance parameter at which thrust efficiency is maximized and generally decreases the overall achievable thrust efficiency. Operational characteristics of two thrusters with inductive coils of different cone angles are explored through thrust stand measurements and time-integrated, unfiltered photography. Trends in impulse bit measurements indicate that, in the present configuration, the thruster with the inductive coil possessing a smaller cone angle produced larger values of thrust, in apparent contradiction to results of the model. Areas of increased light intensity in photographs of thruster operation are assumed to qualitatively represent locations of increased current density. Light intensity is generally greater in images of the thruster with the smaller cone angle when compared to those of the thruster with the larger half cone angle for the same operating conditions, and generally decreases in both

  10. PREFACE: 1982 International Conference on Plasma Physics

    NASA Astrophysics Data System (ADS)

    Wilhelmsson, Hans

    1982-01-01

    Invited Papers: The Physics of Hot Plasmas During the last decade a dramatic evolution of plasma physics has occurred. Not only have gigantic fusion plasma machines been planned, and are now being built, and elaborate spaceships and antenna systems been constructed to explore remote parts of the cosmos; new observations have revealed fascinating structures in space, ranging from pulsar plasmas under extreme conditions in very strong magnetic fields to large-scale magnetic field and electric current systems in cosmic plasmas. X-rays from very distant sources as well as radio-waves from the plasma in the magnetosphere and in the Aurora have recently been studied with new observational techniques. Ingenious laboratory experiments are continuously being carried out to exploit new fundamental processes in plasmas. These are of great interest for the basic understanding of plasmas and also have immediate consequences for applications, like plasma heating and diagnostics. The theoretical description of new plasma phenomena, and of the plasma state in general poses challenging problems, particularly in situations where high concentration of energy is located in the plasmas. Nonlinear wave analysis and turbulence theory have accordingly been extensively developed to describe in particular the collective plasma phenomena. New concepts have been envisaged like plasma solitons, which may be thought of as excitations of local concentrations of longitudinal plasma waves which turn out to be particularly stable. More and more sophisticated structures of nonlinear nature are being revealed by means of high capacity computer facilities. Simulation experiments allow for studies of chaotic behaviour of plasma particles. Related fields of activity form new trends in the development of plasma theory. The programme of the 1982 International Conference on Plasma Physics, which was held in Göteborg, Sweden, stressed the role of the Physics of Hot Plasmas. Studies of such plasmas are

  11. Study on spatial distribution of plasma parameters in a magnetized inductively coupled plasma

    SciTech Connect

    Cheong, Hee-Woon; Lee, Woohyun; Kim, Ji-Won; Whang, Ki-Woong; Kim, Hyuk; Park, Wanjae

    2015-07-15

    Spatial distributions of various plasma parameters such as plasma density, electron temperature, and radical density in an inductively coupled plasma (ICP) and a magnetized inductively coupled plasma (M-ICP) were investigated and compared. Electron temperature in between the rf window and the substrate holder of M-ICP was higher than that of ICP, whereas the one just above the substrate holder of M-ICP was similar to that of ICP when a weak (<8 G) magnetic field was employed. As a result, radical densities in M-ICP were higher than those in ICP and the etch rate of oxide in M-ICP was faster than that in ICP without severe electron charging in 90 nm high aspect ratio contact hole etch.

  12. Low-pressure water-cooled inductively coupled plasma torch

    DOEpatents

    Seliskar, Carl J.; Warner, David K.

    1988-12-27

    An inductively coupled plasma torch is provided which comprises an inner tube, including a sample injection port to which the sample to be tested is supplied and comprising an enlarged central portion in which the plasma flame is confined; an outer tube surrounding the inner tube and containing water therein for cooling the inner tube, the outer tube including a water inlet port to which water is supplied and a water outlet port spaced from the water inlet port and from which water is removed after flowing through the outer tube; and an r.f. induction coil for inducing the plasma in the gas passing into the tube through the sample injection port. The sample injection port comprises a capillary tube including a reduced diameter orifice, projecting into the lower end of the inner tube. The water inlet is located at the lower end of the outer tube and the r.f. heating coil is disposed around the outer tube above and adjacent to the water inlet.

  13. Low-pressure water-cooled inductively coupled plasma torch

    DOEpatents

    Seliskar, C.J.; Warner, D.K.

    1984-02-16

    An inductively coupled plasma torch is provided which comprises an inner tube, including a sample injection port to which the sample to be tested is supplied and comprising an enlarged central portion in which the plasma flame is confined; an outer tube surrounding the inner tube and containing water therein for cooling the inner tube, the outer tube including a water inlet port to which water is supplied and a water outlet port spaced from the water inlet port and from which water is removed after flowing through the outer tube; and an rf induction coil for inducing the plasma in the gas passing into the tube through the sample injection port. The sample injection port comprises a capillary tube including a reduced diameter orifice, projecting into the lower end of the inner tube. The water inlet is located at the lower end of the outer tube and the rf heating coil is disposed around the outer tube above and adjacent to the water inlet.

  14. Negative ion density in inductively coupled chlorine plasmas

    SciTech Connect

    Hebner, G.A.

    1995-12-31

    The negative ion density in radio-frequency (rf) inductively-coupled chlorine discharges has been inferred using laser photodetachment spectroscopy. A Gaseous Electronics Conference (GEC) rf Reference Cell with an inductively coupled plasma source was used to produce the plasma. For this experiment, the chlorine pressure was between 20 and 50 mTorr and the rf power into the plasma was 150 to 250 Watts at 13.56 MHz. Light from a frequency quadrupled Nd:YAG laser (266 nm) was used to photodetach electrons from Cl{sup {minus}}. The time dependent excess electron density was then detected by a microwave interferometer operating at 80 GHz. Based upon the cross section for photodetachment and the measurement geometry, negative ion densities can be calculated. The inferred negative ion densities are at least an order of magnitude higher than the steady state electron density over the parameter space investigated. The dependence of the negative ion density on rf power, gas pressure, flow rate and rf phase will be discussed.

  15. PREFACE: 1982 International Conference on Plasma Physics

    NASA Astrophysics Data System (ADS)

    Wilhelmsson, Hans

    1982-01-01

    Invited Papers: The Physics of Hot Plasmas During the last decade a dramatic evolution of plasma physics has occurred. Not only have gigantic fusion plasma machines been planned, and are now being built, and elaborate spaceships and antenna systems been constructed to explore remote parts of the cosmos; new observations have revealed fascinating structures in space, ranging from pulsar plasmas under extreme conditions in very strong magnetic fields to large-scale magnetic field and electric current systems in cosmic plasmas. X-rays from very distant sources as well as radio-waves from the plasma in the magnetosphere and in the Aurora have recently been studied with new observational techniques. Ingenious laboratory experiments are continuously being carried out to exploit new fundamental processes in plasmas. These are of great interest for the basic understanding of plasmas and also have immediate consequences for applications, like plasma heating and diagnostics. The theoretical description of new plasma phenomena, and of the plasma state in general poses challenging problems, particularly in situations where high concentration of energy is located in the plasmas. Nonlinear wave analysis and turbulence theory have accordingly been extensively developed to describe in particular the collective plasma phenomena. New concepts have been envisaged like plasma solitons, which may be thought of as excitations of local concentrations of longitudinal plasma waves which turn out to be particularly stable. More and more sophisticated structures of nonlinear nature are being revealed by means of high capacity computer facilities. Simulation experiments allow for studies of chaotic behaviour of plasma particles. Related fields of activity form new trends in the development of plasma theory. The programme of the 1982 International Conference on Plasma Physics, which was held in Göteborg, Sweden, stressed the role of the Physics of Hot Plasmas. Studies of such plasmas are

  16. Equivalent circuit effects on mode transitions in H{sub 2} inductively coupled plasmas

    SciTech Connect

    Xu, Hui-Jing; Zhao, Shu-Xia Zhang, Yu-Ru; Gao, Fei; Li, Xue-Chun; Wang, You-Nian

    2015-04-15

    It is well known experimentally that the circuit matching network plays an important role in the mode transition behavior of inductively coupled plasmas. To date, however, there have been no reports of numerical models being used to study the role of the matching circuit in the transition process. In this paper, a new two-dimensional self-consistent fluid model that couples the components of an equivalent circuit module is developed to investigate the effects of the equivalent circuit on the mode transition characteristics of an inductively coupled, hydrogen plasma. The equivalent circuit consists of a current source, impedance matching network, reactor impedance, and plasma transferred impedance. The nonlinear coupling of the external circuit with the internal plasma is investigated by adjusting the matching capacitance at a fixed input current. The electron density and temperature as well as the electromagnetic fields all change suddenly, and the E to H mode transition occurs abruptly at a certain matching capacitance as the impedance matching of the external circuit is varied. We also analyze the fields and the plasma characteristics during the transition process, especially for the case of the capacitive E mode.

  17. Effect of bias application to plasma density in weakly magnetized inductively coupled plasma

    SciTech Connect

    Kim, Hyuk; Lee, Woohyun; Park, Wanjae; Whang, Ki-Woong

    2013-07-15

    Independent control of the ion flux and energy can be achieved in a dual frequency inductively coupled plasma (ICP) system. Typically, the plasma density is controlled by the high-frequency antenna radio-frequency (RF) power and the ion energy is controlled by the low-frequency bias RF power. Increasing the bias power has been known to cause a decrease in the plasma density in capacitively coupled discharge systems as well as in ICP systems. However, an applied axial magnetic field was found to sustain or increase the plasma density as bias power is increased. Measurements show higher electron temperatures but lower plasma densities are obtained in ordinary ICP systems than in magnetized ICP systems under the same neutral gas pressure and RF power levels. Explanations for the difference in the behavior of plasma density with increasing bias power are given in terms of the difference in the heating mechanism in ordinary unmagnetized and magnetized ICP systems.

  18. Ion deposition by inductively coupled plasma mass spectrometry

    SciTech Connect

    Hu, K.; Houk, R.S.

    1996-03-01

    An atmospheric pressure inductively coupled plasma (ICP) is used with a quadrupole mass spectrometer (MS) for ion deposition. The deposited element is introduced as a nebulized aqueous solution. Modifications to the ICP-MS device allow generation and deposition of a mass-resolved beam of {sup 165}Ho{sup +} at 5{times}10{sup 12} ions s{sup {minus}1}. The ICP is a universal, multielement ion source that can potentially be used for applications such as deposition of mixtures of widely varying stoichiometry or of alternating layers of different elements. {copyright} {ital 1996 American Vacuum Society}

  19. Fission Yield Measurements by Inductively Coupled Plasma Mass-Spectrometry

    SciTech Connect

    Irina Glagolenko; Bruce Hilton; Jeffrey Giglio; Daniel Cummings; Karl Grimm; Richard McKnight

    2009-11-01

    Correct prediction of the fission products inventory in irradiated nuclear fuels is essential for accurate estimation of fuel burnup, establishing proper requirements for spent fuel transportation and storage, materials accountability and nuclear forensics. Such prediction is impossible without accurate knowledge of neutron induced fission yields. Unfortunately, the accuracy of the fission yields reported in the ENDF/B-VII.0 library is not uniform across all of the data and much of the improvement is desired for certain isotopes and fission products. We discuss our measurements of cumulative fission yields in nuclear fuels irradiated in thermal and fast reactor spectra using Inductively Coupled Plasma Mass Spectrometry.

  20. Induction plasma calcining of pigment particles for thermal control coatings

    NASA Technical Reports Server (NTRS)

    Farley, E. P.

    1971-01-01

    Induction plasma heating techniques were studied for calcining zinc orthotitanate particles for use in thermal control coatings. Previous studies indicated that the optimum calcining temperature is between 1400 and 1750 C. An intermediate temperature (1670 C) was chosen as a reference point for running a temperature series at the reference point and 220 C on both sides. The effect of varying chamber temperature on the reflectance spectra, before and after vacuum UV irradiation, is presented. The correlation between Zn2Ti04 paramagnetic resonance activity and its susceptibility to vacuum UV damage is discussed.

  1. Effect of Inductive Coil Geometry on the Thrust Efficiency of a Microwave Assisted Discharge Inductive Plasma Accelerator

    NASA Technical Reports Server (NTRS)

    Hallock, Ashley; Polzin, Kurt; Emsellem, Gregory

    2012-01-01

    Pulsed inductive plasma thrusters [1-3] are spacecraft propulsion devices in which electrical energy is capacitively stored and then discharged through an inductive coil. The thruster is electrodeless, with a time-varying current in the coil interacting with a plasma covering the face of the coil to induce a plasma current. Propellant is accelerated and expelled at a high exhaust velocity (O(10-100 km/s)) by the Lorentz body force arising from the interaction of the magnetic field and the induced plasma current. While this class of thruster mitigates the life-limiting issues associated with electrode erosion, pulsed inductive plasma thrusters require high pulse energies to inductively ionize propellant. The Microwave Assisted Discharge Inductive Plasma Accelerator (MAD-IPA) [4, 5] is a pulsed inductive plasma thruster that addressees this issue by partially ionizing propellant inside a conical inductive coil via an electron cyclotron resonance (ECR) discharge. The ECR plasma is produced using microwaves and permanent magnets that are arranged to create a thin resonance region along the inner surface of the coil, restricting plasma formation, and in turn current sheet formation, to a region where the magnetic coupling between the plasma and the inductive coil is high. The use of a conical theta-pinch coil is under investigation. The conical geometry serves to provide neutral propellant containment and plasma plume focusing that is improved relative to the more common planar geometry of the Pulsed Inductive Thruster (PIT) [2, 3], however a conical coil imparts a direct radial acceleration of the current sheet that serves to rapidly decouple the propellant from the coil, limiting the direct axial electromagnetic acceleration in favor of an indirect acceleration mechanism that requires significant heating of the propellant within the volume bounded by the current sheet. In this paper, we describe thrust stand measurements performed to characterize the performance

  2. Induction of stable ER–plasma-membrane junctions by Kv2.1 potassium channels

    PubMed Central

    Fox, Philip D.; Haberkorn, Christopher J.; Akin, Elizabeth J.; Seel, Peter J.; Krapf, Diego; Tamkun, Michael M.

    2015-01-01

    ABSTRACT Junctions between cortical endoplasmic reticulum (cER) and the plasma membrane are a subtle but ubiquitous feature in mammalian cells; however, very little is known about the functions and molecular interactions that are associated with neuronal ER–plasma-membrane junctions. Here, we report that Kv2.1 (also known as KCNB1), the primary delayed-rectifier K+ channel in the mammalian brain, induces the formation of ER–plasma-membrane junctions. Kv2.1 localizes to dense, cell-surface clusters that contain non-conducting channels, indicating that they have a function that is unrelated to membrane-potential regulation. Accordingly, Kv2.1 clusters function as membrane-trafficking hubs, providing platforms for delivery and retrieval of multiple membrane proteins. Using both total internal reflection fluorescence and electron microscopy we demonstrate that the clustered Kv2.1 plays a direct structural role in the induction of stable ER–plasma-membrane junctions in both transfected HEK 293 cells and cultured hippocampal neurons. Glutamate exposure results in a loss of Kv2.1 clusters in neurons and subsequent retraction of the cER from the plasma membrane. We propose Kv2.1-induced ER–plasma-membrane junctions represent a new macromolecular plasma-membrane complex that is sensitive to excitotoxic insult and functions as a scaffolding site for both membrane trafficking and Ca2+ signaling. PMID:25908859

  3. Induction of stable ER-plasma-membrane junctions by Kv2.1 potassium channels.

    PubMed

    Fox, Philip D; Haberkorn, Christopher J; Akin, Elizabeth J; Seel, Peter J; Krapf, Diego; Tamkun, Michael M

    2015-06-01

    Junctions between cortical endoplasmic reticulum (cER) and the plasma membrane are a subtle but ubiquitous feature in mammalian cells; however, very little is known about the functions and molecular interactions that are associated with neuronal ER-plasma-membrane junctions. Here, we report that Kv2.1 (also known as KCNB1), the primary delayed-rectifier K(+) channel in the mammalian brain, induces the formation of ER-plasma-membrane junctions. Kv2.1 localizes to dense, cell-surface clusters that contain non-conducting channels, indicating that they have a function that is unrelated to membrane-potential regulation. Accordingly, Kv2.1 clusters function as membrane-trafficking hubs, providing platforms for delivery and retrieval of multiple membrane proteins. Using both total internal reflection fluorescence and electron microscopy we demonstrate that the clustered Kv2.1 plays a direct structural role in the induction of stable ER-plasma-membrane junctions in both transfected HEK 293 cells and cultured hippocampal neurons. Glutamate exposure results in a loss of Kv2.1 clusters in neurons and subsequent retraction of the cER from the plasma membrane. We propose Kv2.1-induced ER-plasma-membrane junctions represent a new macromolecular plasma-membrane complex that is sensitive to excitotoxic insult and functions as a scaffolding site for both membrane trafficking and Ca(2+) signaling. PMID:25908859

  4. Characterization of the Inductively Heated Plasma Source IPG6-B

    NASA Astrophysics Data System (ADS)

    Dropmann, Michael; Laufer, Rene; Herdrich, Georg; Matthews, Lorin; Hyde, Truell

    2014-10-01

    In close collaboration between the Center for Astrophysics, Space Physics and Engineering Research (CASPER) at Baylor University, Texas, and the Institute of Space Systems (IRS) at the University of Stuttgart, Germany, two plasma facilities have been established using the Inductively heated Plasma Generator 6 (IPG6). The facility at Baylor University (IPG6-B) works at a frequency of 13.56 MHz and a maximum power of 15 kW. A vacuum pump of 160 m3/h in combination with a butterfly valve allows pressure control over a wide range. Intended fields of research include basic investigation into thermo-chemistry and plasma radiation, space plasma environments and high heat fluxes e.g. those found in fusion devices or during atmospheric re-entry of spacecraft. After moving the IPG6-B facility to the Baylor Research and Innovation Collaborative (BRIC) it was placed back into operation during the summer of 2014. Initial characterization in the new lab, using a heat flux probe, Pitot probe and cavity calorimeter, has been conducted for Air, Argon and Helium. The results of this characterization are presented.

  5. Mode transition in CF4 + Ar inductively coupled plasma

    NASA Astrophysics Data System (ADS)

    Liu, Wei; Gao, Fei; Zhao, Shu-Xia; Li, Xue-Chun; Wang, You-Nian

    2013-12-01

    The E to H mode transitions are studied by a hairpin probe and optical emission spectroscopy in inductively coupled CF4 + Ar plasmas. Electron density, optical emission intensity of Ar, and the voltage and current are measured during the E to H mode transitions. It is found that the electron density and plasma emission intensity increase continuously at low pressure during the E to H mode transition, while they jump up discontinuously at high pressure. Meanwhile, the transition threshold power and △P (the power interval between E and H mode) increase by increasing the pressure. When the ratio of CF4 increases, the E to H mode transition happens at higher applied power, and meanwhile, the △P also significantly increases. Besides, the effects of CF4 gas ratio on the plasma properties and the circuit electrical properties in both pure E and H modes were also investigated. The electron density and plasma emission intensity both decrease upon increasing the ratio of CF4 at the two modes, due to the stronger electrons loss scheme. The applied voltages at E and H modes both increase as increasing the CF4 gas ratio, however the applied current at two modes behave just oppositely with the gas ratio.

  6. A study on plasma parameters in various mixed Ar/SF6 inductively coupled plasma

    NASA Astrophysics Data System (ADS)

    Oh, Seung-Ju; Lee, Hyo-Chang; Chung, Chin-Wook

    2011-10-01

    SF6 gas or Ar/SF6 mixing gas is widely used in plasma processes. However, there are a little experimental study with various external parameters such as gas pressures and mixing ratios. In this work, a study of the plasma parameters was done in Ar/SF6 inductively coupled plasma (ICP) from a careful measurement of the electron energy distribution function (EEDF). The measured plasma parameters are compared to the theoretical results with simplified global model. At a low gas pressure, as mixing ratio of SF6 gas increased at a fixed ICP power, electron density decreased and electron temperature increased, but they were not changed largely. However, a remarkable increase in the electron temperature was observed with decrease in the electron density at higher gas pressures. These changes in the plasma parameters could be explained by large electron losses due to the electron attachment and the experimental results were in agreement with the theoretical results.

  7. Matrix effects in inductively coupled plasma mass spectrometry

    SciTech Connect

    Chen, Xiaoshan

    1995-07-07

    The inductively coupled plasma is an electrodeless discharge in a gas (usually Ar) at atmospheric pressure. Radio frequency energy generated by a RF power source is inductively coupled to the plasma gas through a water cooled load coil. In ICP-MS the {open_quotes}Fassel{close_quotes} TAX quartz torch commonly used in emission is mounted horizontally. The sample aerosol is introduced into the central flow, where the gas kinetic temperature is about 5000 K. The aerosol is vaporized, atomized, excited and ionized in the plasma, and the ions are subsequently extracted through two metal apertures (sampler and skimmer) into the mass spectrometer. In ICP-MS, the matrix effects, or non-spectroscopic interferences, can be defined as the type of interferences caused by dissolved concomitant salt ions in the solution. Matrix effects can be divided into two categories: (1) signal drift due to the deposition of solids on the sampling apertures; and/or (2) signal suppression or enhancement by the presence of the dissolved salts. The first category is now reasonably understood. The dissolved salts, especially refractory oxides, tend to deposit on the cool tip of the sampling cone. The clogging of the orifices reduces the ion flow into the ICP-MS, lowers the pressure in the first stage of ICP-MS, and enhances the level of metal oxide ions. Because the extent of the clogging increases with the time, the signal drifts down. Even at the very early stage of the development of ICP-MS, matrix effects had been observed. Houk et al. found out that the ICP-MS was not tolerant to solutions containing significant amounts of dissolved solids.

  8. Control of plasma density distribution via wireless power transfer in an inductively coupled plasma

    NASA Astrophysics Data System (ADS)

    Lee, Hee-Jin; Lee, Hyo-Chang; Kim, Young-Cheol; Chung, Chin-Wook

    2013-06-01

    With an enlargement of the wafer size, development of large-area plasma sources and control of plasma density distribution are required. To control the spatial distribution of the plasma density, wireless power transfer is applied to an inductively coupled plasma for the first time. An inner powered antenna and an outer resonant coil connected to a variable capacitor are placed on the top of the chamber. As the self-resonance frequency ωr of the resonant coil is adjusted, the power transfer rate from the inner powered coil to the outer resonant coil is changed and the dramatic evolution of the plasma density profile is measured. As ωr of the outer resonant coil changes from the non-resonant condition (where ωr is not the driving angular frequency ωrf) to the resonant condition (where ωr = ωrf), the plasma density profile evolves from a convex shape with maximal plasma density at the radial center into a concave shape with maximal plasma density in the vicinity of the resonant antenna coil. This result shows that the plasma density distribution can be successfully controlled via wireless resonance power transfer.

  9. Plasma Characteristics of Large Area Inductively Coupled Plasma System Using Ferrite-Module-Enhanced U-Type Antenna

    NASA Astrophysics Data System (ADS)

    Kim, Kyong Nam; Hyeuk Lim, Jong; Yeom, Geun Young

    2009-11-01

    A ferrite-module-enhanced internal-type linear inductively coupled plasma (ICP) source having multiple U-type antennas operated at 2 MHz has been proposed as a promising candidate to serve as an efficient high-density plasma source for plasma processing areas larger than 2,000×2,300 mm2. When the ICP source was operated at 2 MHz RF power with the ferrite module, high density plasmas on the order of 2.9×1011 cm-3 were obtained at 10 mTorr Ar by applying 4 kW RF power/one U-type antenna; this is 1.5 times higher than the densities obtained at 13.56 MHz without the ferrite module. The higher plasma density obtained with the ICP source operated at 2 MHz with the ferrite module compared with that operated at 13.56 MHz without the ferrite module is related to the magnetic field enhancement caused by the ferrite module. The etch uniformity on a substrate of 2,300×2,000 mm2 at 15 mTorr Ar/O2 (7:3) and about 2.3 kW/U-type antenna was about 11%.

  10. Comparison between experiment and simulation for argon inductively coupled plasma

    SciTech Connect

    Gao Fei; Zhao Shuxia; Li Xiaosong; Wang Younian

    2009-11-15

    In order to include the nonlocal characteristics of electrons and investigate the inductively coupled plasma (ICP) resources more completely, we have developed a hybrid Monte Carlo (MC)/fluid hybrid model and calculated the axial and radial distributions of electron density, electron temperature, plasma potential, and electron energy distribution functions (EEDFs) of Ar discharge in a planar ICP. Furthermore, to make the model more practical, we still incorporate the effects of metastable atoms, whose sets of rate coefficients and density are, respectively, calculated through the electron MC part and fluid module. Besides, the corresponding Langmuir probe measurements are used to compare these data to validate the simulated results. Under all the selected discharge powers and pressures, the theoretically simulated and experimentally measured quantity profiles agree reasonably with each other, embodied in the generally identical magnitude ranges and spatial distributions. Furthermore, the interpretations about their detailed differences are given, which are based on the designs of both experimental schematic and model configuration. The analysis implements that the inclusions of electron-electron collision and a neutral density distribution into the hybrid model are likely to improve the comparison between the model predictions and experiment diagnostics. Furthermore, the evolution of plasma parameters and EEDFs with discharge conditions is discussed.

  11. Thermochemical Nonequilibrium 2D Modeling of Nitrogen Inductively Coupled Plasma Flow

    NASA Astrophysics Data System (ADS)

    Yu, Minghao; Yusuke, Takahashi; Hisashi, Kihara; Ken-ichi, Abe; Kazuhiko, Yamada; Takashi, Abe; Satoshi, Miyatani

    2015-09-01

    Two-dimensional (2D) numerical simulations of thermochemical nonequilibrium inductively coupled plasma (ICP) flows inside a 10-kW inductively coupled plasma wind tunnel (ICPWT) were carried out with nitrogen as the working gas. Compressible axisymmetric Navier-Stokes (N-S) equations coupled with magnetic vector potential equations were solved. A four-temperature model including an improved electron-vibration relaxation time was used to model the internal energy exchange between electron and heavy particles. The third-order accuracy electron transport properties (3rd AETP) were applied to the simulations. A hybrid chemical kinetic model was adopted to model the chemical nonequilibrium process. The flow characteristics such as thermal nonequilibrium, inductive discharge, effects of Lorentz force were made clear through the present study. It was clarified that the thermal nonequilibrium model played an important role in properly predicting the temperature field. The prediction accuracy can be improved by applying the 3rd AETP to the simulation for this ICPWT. supported by Grant-in-Aid for Scientific Research (No. 23560954), sponsored by the Japan Society for the Promotion of Science

  12. Plasma igniter for internal combustion engine

    NASA Technical Reports Server (NTRS)

    Fitzgerald, D. J.; Breshears, R. R. (Inventor)

    1978-01-01

    An igniter for the air/fuel mixture used in the cylinders of an internal combustion engine is described. A conventional spark is used to initiate the discharge of a large amount of energy stored in a capacitor. A high current discharge of the energy in the capacitor switched on by a spark discharge produces a plasma and a magnetic field. The resultant combined electromagnetic current and magnetic field force accelerates the plasma deep into the combustion chamber thereby providing an improved ignition of the air/fuel mixture in the chamber.

  13. Plasma Characteristics Using Superimposed Dual Frequency Inductively Coupled Plasma Source for Next Generation Device Processing.

    PubMed

    Lee, Seung Min; Lee, Chul Hee; Kim, Tae Hyung; Yeom, Geun Young; Kim, Kyong Nam

    2015-11-01

    U-shaped inductively coupled plasma (ICP) source was investigated as a linear plasma source for the next generation roll-to-toll flexible display processing. For the radio frequency power to the source, the dual frequency composed of 13.56 MHz and 2 MHz was used and the effect of dual frequency to the U-shaped ICP source on the plasma density, electron temperature, and plasma uniformity was investigated. As the operating condition, 200 mTorr Ar was used without operating turbo pumps. The use of superimposed dual frequency composed of 13.56 MHz + 2 MHz instead the single frequency of 13.56 MHz increased the plasma density slightly at the same total power. In addition, the addition of 2 MHz rf power to 0.4 kW while maintaining 1 kW 13.56 MHz rf power not only decreased electron temperature but also improved both the plasma uniformity and the process uniformity measured by photoresist etching. Therefore, by using the dual frequency to the U-shaped ICP source, not only the plasma density but also plasma uniformity could be improved in addition to the decrease of possible damage to the substrate. PMID:26726573

  14. Combination induction plasma tube and current concentrator for introducing a sample into a plasma

    DOEpatents

    Hull, Donald E.; Bieniewski, Thomas M.

    1988-01-01

    An induction plasma tube in combination with a current concentrator. The rent concentrator has a substantially cylindrical body having an open end and a partially closed end which defines an aperture. A first slot extends the longitudinal length of the cylindrical body and a second slot extends radially outward from the aperture. Together the first and second slots form a single L-shaped slot. The current concentrator is disposed within a volume bounded by an induction coil substantially along the axis thereof, and when power is applied to the induction coil a concentrated current is induced within the current concentrator aperture. The concentrator is moveable relative to the coil along the longitudinal axis of the coil to control the amount of current which is concentrated at the aperture.

  15. Transition of electron kinetics in weakly magnetized inductively coupled plasmas

    SciTech Connect

    Kim, Jin-Yong; Lee, Hyo-Chang; Kim, Young-Do; Chung, Chin-Wook; Kim, Young-Cheol

    2013-10-15

    Transition of the electron kinetics from nonlocal to local regime was studied in weakly magnetized solenoidal inductively coupled plasma from the measurement of the electron energy probability function (EEPF). Without DC magnetic field, the discharge property was governed by nonlocal electron kinetics at low gas pressure. The electron temperatures were almost same in radial position, and the EEPFs in total electron energy scale were radially coincided. However, when the DC magnetic field was applied, radial non-coincidence of the EEPFs in total electron energy scale was observed. The electrons were cooled at the discharge center where the electron heating is absent, while the electron temperature was rarely changed at the discharge boundary with the magnetic field. These changes show the transition from nonlocal to local electron kinetics and the transition is occurred when the electron gyration diameter was smaller than the skin depth. The nonlocal to local transition point almost coincided with the calculation results by using nonlocal parameter and collision parameter.

  16. Inductively Coupled Plasma Mass Spectrometry Uranium Error Propagation

    SciTech Connect

    Hickman, D P; Maclean, S; Shepley, D; Shaw, R K

    2001-07-01

    The Hazards Control Department at Lawrence Livermore National Laboratory (LLNL) uses Inductively Coupled Plasma Mass Spectrometer (ICP/MS) technology to analyze uranium in urine. The ICP/MS used by the Hazards Control Department is a Perkin-Elmer Elan 6000 ICP/MS. The Department of Energy Laboratory Accreditation Program requires that the total error be assessed for bioassay measurements. A previous evaluation of the errors associated with the ICP/MS measurement of uranium demonstrated a {+-} 9.6% error in the range of 0.01 to 0.02 {micro}g/l. However, the propagation of total error for concentrations above and below this level have heretofore been undetermined. This document is an evaluation of the errors associated with the current LLNL ICP/MS method for a more expanded range of uranium concentrations.

  17. Induction suspension plasma sprayed biological-like hydroxyapatite coatings.

    PubMed

    Loszach, Max; Gitzhofer, François

    2015-04-01

    Substituted hydroxyapatite coatings with different ions (Mg, Na, K, Cl, F) have been developed by the induction suspension plasma spray process. Suspensions were prepared with sol-gel. The main objective of this study was to demonstrate that induction suspension plasma spray technology possesses high material composition flexibility that allows as-sprayed coatings to closely mimic natural bone composition. Long-term in vitro behaviour of as-sprayed substituted coatings was evaluated with simulated body fluid. Data on the suspensions showed the formation of a pure hydroxyapatite phase. Transmission electron microscopy characterized various preparation stages of the suspensions. As-sprayed samples were distinguished by X-ray diffraction and scanning electron microscopy. Substituted elements were quantified by neutron activation. A well-crystallized hydroxyapatite phase was produced with concentration in various substitutions very close to natural bone composition. Ca/P and (Ca + Mg + Na + K)/P ratios provided evidence of the introduction of different cations into apatite structures. The immersion of samples into simulated body fluid led to the nucleation and growth of a flake-like octacalcium phosphate crystal layer at the surface of as-sprayed coatings after one week. Proof of octacalcium phosphate transformation and its partial dissolution and direct re-precipitation into apatite was disclosed by local energy dispersive spectroscopy and microstructure observation. Formation of a Ca/P ratio gradient from the precipitated layer surface to the as-sprayed coatings interface was observed after four weeks once the octacalcium phosphate crystals reached a critical size, resulting in the formation of a rich apatite layer at the interface after six weeks. A set of mechanisms has been proposed to explain these findings. PMID:25586411

  18. Thrust Stand Measurements of the Microwave Assisted Discharge Inductive Plasma Accelerator

    NASA Technical Reports Server (NTRS)

    Hallock, Ashley K.; Polzin, Kurt A.; Emsellem, Gregory D.

    2011-01-01

    Pulsed inductive plasma thrusters [1-3] are spacecraft propulsion devices in which electrical energy is capacitively stored and then discharged through an inductive coil. This type of pulsed thruster is electrodeless, with a time-varying current in the coil interacting with a plasma covering the face of the coil to induce a plasma current. Propellant is accelerated and expelled at a high exhaust velocity (O(10-100 km/s)) by the Lorentz body force arising from the interaction of the magnetic field and the induced plasma current. While this class of thruster mitigates the life-limiting issues associated with electrode erosion, pulsed inductive plasma thrusters require high pulse energies to inductively ionize propellant. The Microwave Assisted Dis- charge Inductive Plasma Accelerator (MAD-IPA), shown in Fig. 1, is a pulsed inductive plasma thruster that addressees this issue by partially ionizing propellant inside a conical inductive coil before the main current pulse via an electron cyclotron resonance (ECR) discharge. The ECR plasma is produced using microwaves and a static magnetic field from a set of permanent magnets arranged to create a thin resonance region along the inner surface of the coil, restricting plasma formation, and in turn current sheet formation, to a region where the magnetic coupling between the plasma and the theta-pinch coil is high. The use of a conical theta-pinch coil also serves to provide neutral propellant containment and plasma plume focusing that is improved relative to the more common planar geometry of the Pulsed Inductive Thruster (PIT) [1, 2]. In this paper, we describe thrust stand measurements performed to characterize the performance (specific impulse, thrust efficiency) of the MAD-IPA thruster. Impulse data are obtained at various pulse energies, mass flow rates and inductive coil geometries. Dependencies on these experimental parameters are discussed in the context of the current sheet formation and electromagnetic plasma

  19. Port fuel injection and induction system for internal combustion engine

    SciTech Connect

    Bishai, M.N.

    1991-04-23

    This patent describes an engine having a valve cover with a PVC valve to vent a valve chamber so as to eliminate oil and gas fumes there from and an automotive fuel injection system having a port fuel injector connected to a fuel supply and to an air manifold for injecting an air/fuel mixture into the injector for producing a fuel spray pattern at the outlet of an air induction passage form a throttle body assembly and upstream of an inlet valve to the combustion chamber of an internal combustion engine characterized by an integral electric motor driven pump assembly means supplying the injection air to the air manifold; the motor pump assembly means having a pump inlet connected to the PVC valve for providing a lubrication mist to the pump during the operation thereof and the motor pump assembly means having a pump outlet connected to the inlet of the air manifold.

  20. Effect of Inductive Coil Geometry and Current Sheet Trajectory of a Conical Theta Pinch Pulsed Inductive Plasma Accelerator

    NASA Technical Reports Server (NTRS)

    Hallock, Ashley K.; Polzin, Kurt A.; Bonds, Kevin W.; Emsellem, Gregory D.

    2011-01-01

    Results are presented demonstrating the e ect of inductive coil geometry and current sheet trajectory on the exhaust velocity of propellant in conical theta pinch pulsed induc- tive plasma accelerators. The electromagnetic coupling between the inductive coil of the accelerator and a plasma current sheet is simulated, substituting a conical copper frustum for the plasma. The variation of system inductance as a function of plasma position is obtained by displacing the simulated current sheet from the coil while measuring the total inductance of the coil. Four coils of differing geometries were employed, and the total inductance of each coil was measured as a function of the axial displacement of two sep- arate copper frusta both having the same cone angle and length as the coil but with one compressed to a smaller size relative to the coil. The measured relationship between total coil inductance and current sheet position closes a dynamical circuit model that is used to calculate the resulting current sheet velocity for various coil and current sheet con gura- tions. The results of this model, which neglects the pinching contribution to thrust, radial propellant con nement, and plume divergence, indicate that in a conical theta pinch ge- ometry current sheet pinching is detrimental to thruster performance, reducing the kinetic energy of the exhausting propellant by up to 50% (at the upper bound for the parameter range of the study). The decrease in exhaust velocity was larger for coils and simulated current sheets of smaller half cone angles. An upper bound for the pinching contribution to thrust is estimated for typical operating parameters. Measurements of coil inductance for three di erent current sheet pinching conditions are used to estimate the magnetic pressure as a function of current sheet radial compression. The gas-dynamic contribution to axial acceleration is also estimated and shown to not compensate for the decrease in axial electromagnetic acceleration

  1. Investigation of Asymmetries in Inductively Coupled Plasma Etching Reactors Using a 3-Dimensional Hybrid Model

    NASA Astrophysics Data System (ADS)

    Kushner, Mark J.; Grapperhaus, Michael J.

    1996-10-01

    Inductively Coupled Plasma (ICP) reactors have the potential for scaling to large area substrates while maintaining azimuthal symmetry or side-to-side uniformity across the wafer. Asymmetric etch properties in these devices have been attributed to transmission line properties of the coil, internal structures (such as wafer clamps) and non-uniform gas injection or pumping. To investigate the origins of asymmetric etch properties, a 3-dimensional hybrid model has been developed. The hybrid model contains electromagnetic, electric circuit, electron energy equation, and fluid modules. Continuity and momentum equations are solved in the fluid module along with Poisson's equation. We will discuss results for ion and radical flux uniformity to the substrate while varying the transmission line characteristics of the coil, symmetry of gas inlets/pumping, and internal structures. Comparisons will be made to expermental measurements of etch rates. ^*Work supported by SRC, NSF, ARPA/AFOSR and LAM Research.

  2. Heavy metals in aromatic spices by inductively coupled plasma-mass spectrometry.

    PubMed

    Bua, Daniel Giuseppe; Annuario, Giovanni; Albergamo, Ambrogina; Cicero, Nicola; Dugo, Giacomo

    2016-09-01

    Objective of this study was to determine the content of Cd, Hg, As and Pb in common spices traded in the Italian market, using inductively coupled plasma-mass spectrometry (ICP-MS). The results were compared with the maximum limits established by the national Legislative Decree (LD) no. 107 implementing the Council Directive 88/388/EEC and by international organisations, such as Food and Agriculture Organization (FAO) and World Health Organization (WHO). Food safety for spices was assessed considering the tolerable weekly intake (TWI) and the provisional tolerable weekly intake (PTWI), respectively, for Cd and Hg and the 95% lower confidence limit of the benchmark dose of 1% extra risk (BMDL01) for As and Pb. Investigated elements in all samples were within the maximum limits as set by the national and international normative institutions. Nevertheless, the heavy metal content of some spices exceeded the PTWI, TWI and BMDL01, which needs attention when considering consumer's health. PMID:27074712

  3. Diagnostics of Argon Inductively Coupled Plasma and Dielectric Barrier Discharge Plasma by Optical Emission Spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhang, Jia-liang; Yu, Shi-ji; Ma, Teng-cai; Deng, Xin-lu

    2001-08-01

    An experimental setup was built up to carry out radio frequency (RF) inductively coupled plasma (ICP) and dielectric barrier discharge (DBD), and to depict the optical emission spectra (OES) of the discharges. OES from argon ICP and DBD plasmas in visible and near ultraviolet region were measured. For argon ICP, the higher RF power input (higher than 500 W for our machine), the higher degree of argon plasma ionization. But that doesn't mean a higher mean electron energy. With the increase in the power input, the mean electron energy increases slightly, whereas the density of electron increases apparently. Or, the contrary, argon DBD discharge behaves in the manner of a pulsed DC discharge on optical emission spectroscopy and V-I characteristics. DBD current is composed of a series of pulses equally spaced in temporal domain. The kinetics of DBD emission strength is mainly governed by the frequency of the current pulse.

  4. Mechanism for Plasma Etching of Shallow Trench Isolation Features in an Inductively Coupled Plasma

    NASA Astrophysics Data System (ADS)

    Agarwal, Ankur; Rauf, Shahid; He, Jim; Choi, Jinhan; Collins, Ken

    2011-10-01

    Plasma etching for microelectronics fabrication is facing extreme challenges as processes are developed for advanced technological nodes. As device sizes shrink, control of shallow trench isolation (STI) features become more important in both logic and memory devices. Halogen-based inductively coupled plasmas in a pressure range of 20-60 mTorr are typically used to etch STI features. The need for improved performance and shorter development cycles are placing greater emphasis on understanding the underlying mechanisms to meet process specifications. In this work, a surface mechanism for STI etch process will be discussed that couples a fundamental plasma model to experimental etch process measurements. This model utilizes ion/neutral fluxes and energy distributions calculated using the Hybrid Plasma Equipment Model. Experiments are for blanket Si wafers in a Cl2/HBr/O2/N2 plasma over a range of pressures, bias powers, and flow rates of feedstock gases. We found that kinetic treatment of electron transport was critical to achieve good agreement with experiments. The calibrated plasma model is then coupled to a string-based feature scale model to quantify the effect of varying process parameters on the etch profile. We found that the operating parameters strongly influence critical dimensions but have only a subtle impact on the etch depths.

  5. Characteristics of pulsed dual frequency inductively coupled plasma

    NASA Astrophysics Data System (ADS)

    Seo, Jin Seok; Kim, Kyoung Nam; Kim, Ki Seok; Kim, Tae Hyung; Yeom, Geun Young

    2015-01-01

    To control the plasma characteristics more efficiently, a dual antenna inductively coupled plasma (DF-ICP) source composed of a 12-turn inner antenna operated at 2 MHz and a 3-turn outer antenna at 13.56 MHz was pulsed. The effects of pulsing to each antenna on the change of plasma characteristics and SiO2 etch characteristics using Ar/C4F8 gas mixtures were investigated. When the duty percentage was decreased from continuous wave (CW) mode to 30% for the inner or outer ICP antenna, decrease of the average electron temperature was observed for the pulsing of each antenna. Increase of the CF2/F ratio was also observed with decreasing duty percentage of each antenna, indicating decreased dissociation of the C4F8 gas due to the decreased average electron temperature. When SiO2 etching was investigated as a function of pulse duty percentage, increase of the etch selectivity of SiO2 over amorphous carbon layer (ACL) was observed while decreasing the SiO2 etch rate. The increase of etch selectivity was related to the change of gas dissociation characteristics, as observed by the decrease of average electron temperature and consequent increase of the CF2/F ratio. The decrease of the SiO2 etch rate could be compensated for by using the rf power compensated mode, that is, by maintaining the same time-average rf power during pulsing, instead of using the conventional pulsing mode. Through use of the power compensated mode, increased etch selectivity of SiO2/ACL similar to the conventional pulsing mode could be observed without significant decrease of the SiO2 etch rate. Finally, by using the rf power compensated mode while pulsing rf powers to both antennas, the plasma uniformity over the 300 mm diameter substrate could be improved from 7% for the CW conditions to about around 3.3% with the duty percentage of 30%.

  6. Aerosol detection efficiency in inductively coupled plasma mass spectrometry

    DOE PAGESBeta

    Hubbard, Joshua A.; Zigmond, Joseph A.

    2016-03-02

    We used an electrostatic size classification technique to segregate particles of known composition prior to being injected into an inductively coupled plasma mass spectrometer (ICP-MS). Moreover, we counted size-segregated particles with a condensation nuclei counter as well as sampled with an ICP-MS. By injecting particles of known size, composition, and aerosol concentration into the ICP-MS, efficiencies of the order of magnitude aerosol detection were calculated, and the particle size dependencies for volatile and refractory species were quantified. Similar to laser ablation ICP-MS, aerosol detection efficiency was defined as the rate at which atoms were detected in the ICP-MS normalized bymore » the rate at which atoms were injected in the form of particles. This method adds valuable insight into the development of technologies like laser ablation ICP-MS where aerosol particles (of relatively unknown size and gas concentration) are generated during ablation and then transported into the plasma of an ICP-MS. In this study, we characterized aerosol detection efficiencies of volatile species gold and silver along with refractory species aluminum oxide, cerium oxide, and yttrium oxide. Aerosols were generated with electrical mobility diameters ranging from 100 to 1000 nm. In general, it was observed that refractory species had lower aerosol detection efficiencies than volatile species, and there were strong dependencies on particle size and plasma torch residence time. Volatile species showed a distinct transition point at which aerosol detection efficiency began decreasing with increasing particle size. This critical diameter indicated the largest particle size for which complete particle detection should be expected and agreed with theories published in other works. Aerosol detection efficiencies also displayed power law dependencies on particle size. Aerosol detection efficiencies ranged from 10-5 to 10-11. Free molecular heat and mass transfer theory was

  7. Behavior of Excited Argon Atoms in Inductively Driven Plasmas

    SciTech Connect

    HEBNER,GREGORY A.; MILLER,PAUL A.

    1999-12-07

    Laser induced fluorescence has been used to measure the spatial distribution of the two lowest energy argon excited states, 1s{sub 5} and 1s{sub 4}, in inductively driven plasmas containing argon, chlorine and boron trichloride. The behavior of the two energy levels with plasma conditions was significantly different, probably because the 1s{sub 5} level is metastable and the 1s{sub 4} level is radiatively coupled to the ground state but is radiation trapped. The argon data is compared with a global model to identify the relative importance of processes such as electron collisional mixing and radiation trapping. The trends in the data suggest that both processes play a major role in determining the excited state density. At lower rfpower and pressure, excited state spatial distributions in pure argon were peaked in the center of the discharge, with an approximately Gaussian profile. However, for the highest rfpowers and pressures investigated, the spatial distributions tended to flatten in the center of the discharge while the density at the edge of the discharge was unaffected. The spatially resolved excited state density measurements were combined with previous line integrated measurements in the same discharge geometry to derive spatially resolved, absolute densities of the 1s{sub 5} and 1s{sub 4} argon excited states and gas temperature spatial distributions. Fluorescence lifetime was a strong fi.mction of the rf power, pressure, argon fraction and spatial location. Increasing the power or pressure resulted in a factor of two decrease in the fluorescence lifetime while adding Cl{sub 2} or BCl{sub 3} increased the fluorescence lifetime. Excited state quenching rates are derived from the data. When Cl{sub 2} or BCl{sub 3} was added to the plasma, the maximum argon metastable density depended on the gas and ratio. When chlorine was added to the argon plasma, the spatial density profiles were independent of chlorine fraction. While it is energetically possible for

  8. Aerosol detection efficiency in inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Hubbard, Joshua A.; Zigmond, Joseph A.

    2016-05-01

    An electrostatic size classification technique was used to segregate particles of known composition prior to being injected into an inductively coupled plasma mass spectrometer (ICP-MS). Size-segregated particles were counted with a condensation nuclei counter as well as sampled with an ICP-MS. By injecting particles of known size, composition, and aerosol concentration into the ICP-MS, efficiencies of the order of magnitude aerosol detection were calculated, and the particle size dependencies for volatile and refractory species were quantified. Similar to laser ablation ICP-MS, aerosol detection efficiency was defined as the rate at which atoms were detected in the ICP-MS normalized by the rate at which atoms were injected in the form of particles. This method adds valuable insight into the development of technologies like laser ablation ICP-MS where aerosol particles (of relatively unknown size and gas concentration) are generated during ablation and then transported into the plasma of an ICP-MS. In this study, we characterized aerosol detection efficiencies of volatile species gold and silver along with refractory species aluminum oxide, cerium oxide, and yttrium oxide. Aerosols were generated with electrical mobility diameters ranging from 100 to 1000 nm. In general, it was observed that refractory species had lower aerosol detection efficiencies than volatile species, and there were strong dependencies on particle size and plasma torch residence time. Volatile species showed a distinct transition point at which aerosol detection efficiency began decreasing with increasing particle size. This critical diameter indicated the largest particle size for which complete particle detection should be expected and agreed with theories published in other works. Aerosol detection efficiencies also displayed power law dependencies on particle size. Aerosol detection efficiencies ranged from 10- 5 to 10- 11. Free molecular heat and mass transfer theory was applied, but

  9. Complex image method for RF antenna-plasma inductive coupling calculation in planar geometry. Part I: basic concepts

    NASA Astrophysics Data System (ADS)

    Howling, A. A.; Guittienne, Ph; Jacquier, R.; Furno, I.

    2015-12-01

    The coupling between an inductive source and the plasma determines the power transfer efficiency and the reflected impedance in the primary circuit. Usually, the plasma coupling is analysed by means of a transformer equivalent circuit, where the plasma inductance and resistance are estimated using a global plasma model. This paper shows that, for planar RF antennas, the mutual inductance between the plasma and the primary circuit can be calculated using partial inductances and the complex image method, where the plasma coupling is determined in terms of the plasma skin depth and the distance to the plasma. To introduce the basic concepts, the mutual inductance is calculated here for a linear conductor parallel to the plasma surface. In the accompanying paper part II Guittienne et al (2015 Plasma Sources Sci. Technol. 24 065015), impedance measurements on a RF resonant planar plasma source are modeled using an impedance matrix where the plasma-antenna mutual impedances are calculated using the complex image method presented here.

  10. Inductively coupled plasma etching of BZN thin films in SF6/Ar plasmas

    NASA Astrophysics Data System (ADS)

    Wang, Gang; Li, Ping; Zhang, Guojun; Li, Wei; Dai, Liping; Jiang, Jing

    2013-03-01

    Etching mechanisms and characteristics of bismuth zinc niobate (BZN) thin films were investigated in inductively coupled SF6/Ar plasmas. The influences of various etching parameters including the gas flow ratio, process pressure, and ICP power on the etching results were analyzed. It is found that the chemical etching with F radicals was more effective than the physical sputtering etching with Ar ions for the inductively coupled plasma etching of BZN thin films. The mechanism of ion assisted chemical etching of BZN thin films in SF6/Ar plasmas was proposed. A maximum etch rate of approximately 43.15 nm/min for the BZN thin film was obtained at the optimum etching conditions: 3/2 for the SF6/Ar gas flow ratio, 10 mTorr for the process pressure, and 600 W for the ICP power. The surface morphology of the etched BZN thin film was observed, where was smooth and clean and no post-etch residues were remained.

  11. External control of electron energy distributions in a dual tandem inductively coupled plasma

    SciTech Connect

    Liu, Lei; Sridhar, Shyam; Zhu, Weiye; Donnelly, Vincent M. Economou, Demetre J.; Logue, Michael D.; Kushner, Mark J.

    2015-08-28

    The control of electron energy probability functions (EEPFs) in low pressure partially ionized plasmas is typically accomplished through the format of the applied power. For example, through the use of pulse power, the EEPF can be modulated to produce shapes not possible under continuous wave excitation. This technique uses internal control. In this paper, we discuss a method for external control of EEPFs by transport of electrons between separately powered inductively coupled plasmas (ICPs). The reactor incorporates dual ICP sources (main and auxiliary) in a tandem geometry whose plasma volumes are separated by a grid. The auxiliary ICP is continuously powered while the main ICP is pulsed. Langmuir probe measurements of the EEPFs during the afterglow of the main ICP suggests that transport of hot electrons from the auxiliary plasma provided what is effectively an external source of energetic electrons. The tail of the EEPF and bulk electron temperature were then elevated in the afterglow of the main ICP by this external source of power. Results from a computer simulation for the evolution of the EEPFs concur with measured trends.

  12. Inductively coupled plasma mass spectrometry in the analysis of biological samples and pharmaceutical drugs

    NASA Astrophysics Data System (ADS)

    Ossipov, K.; Seregina, I. F.; Bolshov, M. A.

    2016-04-01

    Inductively coupled plasma mass spectrometry (ICP-MS) is widely used in the analysis of biological samples (whole blood, serum, blood plasma, urine, tissues, etc.) and pharmaceutical drugs. The shortcomings of this method related to spectral and non-spectral interferences are manifested in full measure in determination of the target analytes in these complex samples strongly differing in composition. The spectral interferences are caused by similarity of masses of the target component and sample matrix components. Non-spectral interferences are related to the influence of sample matrix components on the physicochemical processes taking place during formation and transportation of liquid sample aerosols into the plasma, on the value and spatial distribution of plasma temperature and on the transmission of the ion beam from the interface to mass spectrometer detector. The review is devoted to analysis of different mechanisms of appearance of non-spectral interferences and to ways for their minimization or elimination. Special attention is paid to the techniques of biological sample preparation, which largely determine the mechanisms of the influence of sample composition on the results of element determination. The ways of lowering non-spectral interferences by instrumental parameter tuning and application of internal standards are considered. The bibliography includes 189 references.

  13. Feedback control of plasma electron density and ion energy in an inductively coupled plasma etcher

    SciTech Connect

    Lin Chaung; Leou, K.-C.; Huang, H.-M.; Hsieh, C.-H.

    2009-01-15

    Here the authors report the development of a fuzzy logic based feedback control of the plasma electron density and ion energy for high density plasma etch process. The plasma electron density was measured using their recently developed transmission line microstrip microwave interferometer mounted on the chamber wall, and the rf voltage was measured by a commercial impedance meter connected to the wafer stage. The actuators were two 13.56 MHz rf power generators which provided the inductively coupled plasma power and bias power, respectively. The control system adopted the fuzzy logic control algorithm to reduce frequent actuator action resulting from measurement noise. The experimental results show that the first wafer effect can be eliminated using closed-loop control for both poly-Si and HfO{sub 2} etching. In particular, for the HfO2 etch, the controlled variables in this work were much more effective than the previous one where ion current was controlled, instead of the electron density. However, the pressure disturbance effect cannot be reduced using plasma electron density feedback.

  14. Etch Process Sensitivity To An Inductively Coupled Plasma Etcher Treated With Fluorine-Based Plasma

    NASA Astrophysics Data System (ADS)

    Xu, Songlin; Sun, Zhiwen; Qian, Xueyu; Yin, Gerald

    1997-10-01

    Significant etch rate drop after the treatment of an etch chamber with Fluorine-based plasma has been found for some silicon etch processes on an inductively coupled plasma reactor, which might cause problems in IC production line once the etch chamber runs alternative processes with F-based and F-free chemistry, or needs frequent cleaning with F-plasma. In this work, a systematic study of the root cause of process sensitivity to the etch chamber treated with F-plasma has been conducted. The experimental results show that pressure is a key factor to affect the etch rate drop. Processes at high pressure are more sensitive than those at low pressure because the quenching of neutral reactive species becomes more severe after the F-treatment. O2 addition also increases the etch rate sensitivity, basically due to higher O2(subscript: )concentration after F-treatment which enhances the oxidation of silicon. The EDX and XPS elemental analysis of the chamber interior wall reveals a significant composition change after the interaction with F-plasma, the altered surface might accelerate the recombination of free radical species.

  15. Determination of the rare-earth elements in geological materials by inductively coupled plasma mass spectrometry

    USGS Publications Warehouse

    Lichte, F.E.; Meier, A.L.; Crock, J.G.

    1987-01-01

    A method of analysis of geological materials for the determination of the rare-earth elements using the Inductively coupled plasma mass spectrometric technique (ICP-MS) has been developed. Instrumental parameters and factors affecting analytical results have been first studied and then optimized. Samples are analyzed directly following an acid digestion, without the need for separation or preconcentration with limits of detection of 2-11 ng/g, precision of ?? 2.5% relative standard deviation, and accuracy comparable to inductively coupled plasma emission spectrometry and instrumental neutron activation analysis. A commercially available ICP-MS instrument is used with modifications to the sample introduction system, torch, and sampler orifice to reduce the effects of high salt content of sample solutions prepared from geologic materials. Corrections for isobaric interferences from oxide ions and other diatomic and triatomic ions are made mathematically. Special internal standard procedures are used to compensate for drift in metahmetal oxide ratios and sensitivity. Reference standard values are used to verify the accuracy and utility of the method.

  16. A study on the maximum power transfer condition in an inductively coupled plasma using transformer circuit model

    SciTech Connect

    Kim, Young-Do; Lee, Hyo-Chang; Chung, Chin-Wook

    2013-09-15

    Correlations between the external discharge parameters (the driving frequency ω and the chamber dimension R) and plasma characteristics (the skin depth δ and the electron-neutral collision frequency ν{sub m}) are studied using the transformer circuit model [R. B. Piejak et al., Plasma Sources Sci. Technol. 1, 179 (1992)] when the absorbed power is maximized in an inductively coupled plasma. From the analysis of the transformer circuit model, the maximum power transfer conditions, which depend on the external discharge parameters and the internal plasma characteristics, were obtained. It was found that a maximum power transfer occurs when δ≈0.38R for the discharge condition at which ν{sub m}/ω≪1, while it occurs when δ≈√(2)√(ω/ν{sub m})R for the discharge condition at which ν{sub m}/ω≫1. The results of this circuit analysis are consistent with the stable last inductive mode region of an inductive-to-capacitive mode transition [Lee and Chung, Phys. Plasmas 13, 063510 (2006)], which was theoretically derived from Maxwell's equations. Our results were also in agreement with the experimental results. From this work, we demonstrate that a simple circuit analysis can be applied to explain complex physical phenomena to a certain extent.

  17. Induced magnetic-field effects in inductively coupled plasmas

    SciTech Connect

    Cohen, R.H.; Rognlien, T.D.

    1995-11-04

    In inductive plasma sources, the rapid spatial decay of the electric field arising from the skin effect produces a large radio frequency (RF) magnetic field via Faraday`s law. We previously determined that this magnetic field leads to a reduction of the electron density in the skin region, as well as a reduction in the collisionless heating rate. The electron deficit leads to the formation of an electrostatic potential which pulls electrons in to restore quasineutrality. Here we calculate the electron density including both the induced and electrostatic fields. If the wave frequency is not too low, the ions respond only to the averaged fields, and hence the electrostatic field is oscillatory, predominantly at the second harmonic of the applied field. We calculate the potential required to establish a constant electron density, and compare with numerical orbit-code calculations. For times short compared to ion transit times, the quasineutral density is just the initial ion density. For timescales long enough that the ions can relax, the density profile can be found from the solution of fluid equations with an effective (ponderomotive-like) potential added. Although the time-varying electrostatic potential is an extra source of heating, the net effect of the induced magnetic and electrostatic fields through trapping, early turning, and direct heating is a significant reduction in collisionless heating for parameters of interest.

  18. Temporal Analysis of Electrostatic Chuck Characteristics in Inductively Coupled Plasma

    NASA Astrophysics Data System (ADS)

    Shim, Gyu Il; Sugai, Hideo

    Johnsen-Rahbek electrostatic chuck (ESC) for holding a silicon wafer in semiconductor processing is investigated in inductively coupled plasma (ICP). Bi-layer model of the ESC consisting of a thick bulk layer and a thin interface layer is proposed. The resistance of each layer is obtained by measuring the ESC voltage-current (V-I) characteristic with and without the wafer in ICP, along with the voltage effectively applied to the interface layer. Surface charges stored in the interface layer capacitance are found by the time-integration of current in a turn-on phase of a ramped voltage. On the other hand, the chuck holding force is in situ obtained in a turn-off phase of slowly ramped voltage, from the critical conditions of helium gas pressurization for wafer de-chuck. The electrostatic force predicted on a basis of equivalent circuit in the bi-layer model coincides with the mechanical force obtained in the wafer de-touch experiments.

  19. Inductively Coupled Plasma Zoom-Time-of-Flight Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Dennis, Elise A.; Ray, Steven J.; Enke, Christie G.; Hieftje, Gary M.

    2016-03-01

    A zoom-time-of-flight mass spectrometer has been coupled to an inductively coupled plasma (ICP) ionization source. Zoom-time-of-flight mass spectrometry (zoom-TOFMS) combines two complementary types of velocity-based mass separation. Specifically, zoom-TOFMS alternates between conventional, constant-energy acceleration (CEA) TOFMS and energy-focused, constant-momentum acceleration (CMA) (zoom) TOFMS. The CMA mode provides a mass-resolution enhancement of 1.5-1.7× over CEA-TOFMS in the current, 35-cm ICP-zoom-TOFMS instrument geometry. The maximum resolving power (full-width at half-maximum) for the ICP-zoom-TOFMS instrument is 1200 for CEA-TOFMS and 1900 for CMA-TOFMS. The CMA mode yields detection limits of between 0.02 and 0.8 ppt, depending upon the repetition rate and integration time—compared with single ppt detection limits for CEA-TOFMS. Isotope-ratio precision is shot-noise limited at approximately 0.2% relative-standard deviation (RSD) for both CEA- and CMA-TOFMS at a 10 kHz repetition rate and an integration time of 3-5 min. When the repetition rate is increased to 43.5 kHz for CMA, the shot-noise limited, zoom-mode isotope-ratio precision is improved to 0.09% RSD for the same integration time.

  20. Design and Testing of a Small Inductive Pulsed Plasma Thruster

    NASA Technical Reports Server (NTRS)

    Martin, Adam K.; Dominguez, Alexandra; Eskridge, Richard H.; Polzin, Kurt A.; Riley, Daniel P.; Perdue, Kevin A.

    2015-01-01

    The design and testing of a small inductive pulsed plasma thruster (IPPT) is described. The device was built as a test-bed for the pulsed gas-valves and solid-state switches required for a thruster of this kind, and was designed to be modular to facilitate modification. The thruster in its present configuration consists of a multi-turn, spiral-wound acceleration coil (270 millimeters outer diameter, 100 millimeters inner diameter) driven by a 10 microfarad capacitor and switched with a high-voltage thyristor, a propellant delivery system including a fast pulsed gas-valve, and a glow-discharge pre-ionizer circuit. The acceleration coil circuit may be operated at voltages up to 4 kilovolts (the thyristor limit is 4.5 kilovolts) and the thruster operated at cyclic-rates up to 30 Herz. Initial testing of the thruster, both bench-top and in-vacuum, has been performed. Cyclic operation of the complete device was demonstrated (at 2 Herz), and a number of valuable insights pertaining to the design of these devices have been gained.

  1. Gold fingerprinting by laser ablation inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Watling, R. John; Herbert, Hugh K.; Delev, Dianne; Abell, Ian D.

    1994-02-01

    Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been applied to the characterization of the trace element composition "fingerprint" of selected gold samples from Western Australia and South Africa. By comparison of the elemental associations it is possible to relate gold to a specific mineralizing event, mine or bullion sample. This methodology facilitates identification of the provenance of stolen gold or gold used in salting activities. In this latter case, it is common for gold from a number of sources to be used in the salting process. Consequently, gold in the prospect being salted will not come from a single source and identification of multiple sources for this gold will establish that salting has occurred. Preliminary results also indicate that specific elemental associations could be used to identify the country of origin of gold. The technique has already been applied in 17 cases involving gold theft in Western Australia, where it is estimated that up to 2% of gold production is "relocated" each year as a result of criminal activities.

  2. Uranium quantification in semen by inductively coupled plasma mass spectrometry.

    PubMed

    Todorov, Todor I; Ejnik, John W; Guandalini, Gustavo; Xu, Hanna; Hoover, Dennis; Anderson, Larry; Squibb, Katherine; McDiarmid, Melissa A; Centeno, Jose A

    2013-01-01

    In this study we report uranium analysis for human semen samples. Uranium quantification was performed by inductively coupled plasma mass spectrometry. No additives, such as chymotrypsin or bovine serum albumin, were used for semen liquefaction, as they showed significant uranium content. For method validation we spiked 2g aliquots of pooled control semen at three different levels of uranium: low at 5 pg/g, medium at 50 pg/g, and high at 1000 pg/g. The detection limit was determined to be 0.8 pg/g uranium in human semen. The data reproduced within 1.4-7% RSD and spike recoveries were 97-100%. The uranium level of the unspiked, pooled control semen was 2.9 pg/g of semen (n=10). In addition six semen samples from a cohort of Veterans exposed to depleted uranium (DU) in the 1991 Gulf War were analyzed with no knowledge of their exposure history. Uranium levels in the Veterans' semen samples ranged from undetectable (<0.8 pg/g) to 3350 pg/g. This wide concentration range for uranium in semen is consistent with known differences in current DU body burdens in these individuals, some of whom have retained embedded DU fragments. PMID:22944582

  3. Modeling and simulation of ion-filtered inductively coupled plasma using argon plasma

    NASA Astrophysics Data System (ADS)

    Wu, Chao; Wang, Jian; Zhang, Weiwang; Luo, Yi

    2015-03-01

    An ion-filtered inductively coupled plasma (IF-ICP) is proposed to reduce ion bombardment and provide high metastable species density for chemical vapor deposition. Argon plasma, which has simple reaction mechanism, is simulated to show the effects of ion filter. Compared to typical ICP, the maximum density of ions of IF-ICP is lower while that of metastable species is higher. The filter can absorb ions effectively and relatively small amount of metastable species, with the absorption coefficient proportional to its surface area. A proper gap between filter and substrate can achieve more metastable species and less ions on the substrate. The pressure and RF power need to be optimized based on the tradeoff between deposition rate and ion damage. The density of ions on the substrate can be reduced by two orders of magnitude while that of metastable species are maintained in the order of 1017 m-3 under the optimized conditions.

  4. Vacuum arc plasma thrusters with inductive energy storage driver

    NASA Technical Reports Server (NTRS)

    Krishnan, Mahadevan (Inventor)

    2009-01-01

    A plasma thruster with a cylindrical inner and cylindrical outer electrode generates plasma particles from the application of energy stored in an inductor to a surface suitable for the formation of a plasma and expansion of plasma particles. The plasma production results in the generation of charged particles suitable for generating a reaction force, and the charged particles are guided by a magnetic field produced by the same inductor used to store the energy used to form the plasma.

  5. Evolution of plasma parameters in a He - N2/Ar magnetic pole enhanced inductive plasma source

    NASA Astrophysics Data System (ADS)

    Younus, Maria; Rehman, N. U.; Shafiq, M.; Zakaullah, M.; Abrar, M.

    2016-02-01

    A magnetic pole enhanced inductively coupled H e - N2/A r plasma is studied at low pressure, to monitor the effects of helium mixing on plasma parameters like electron number density (ne) , electron temperature (Te) , plasma potential (Vp ) , and electron energy probability functions (EEPFs). An RF compensated Langmuir probe is employed to measure these plasma parameters. It is noted that electron number density increases with increasing RF power and helium concentration in the mixture, while it decreases with increase in filling gas pressure. On the other hand, electron temperature shows an increasing trend with helium concentration in the mixture. At low RF powers and low helium concentration in the mixture, EEPFs show a "bi-Maxwellian" distribution with pressure. While at RF powers greater than 50 W and higher helium concentration in the mixture, EEPFs evolve into "Maxwellian" distribution. The variation of skin depth with RF power and helium concentration in the mixture, and its relation with EEPF are also studied. The effect of helium concentrations on the temperatures of two electron groups ( Tb u l k and Tt a i l ) in the "bi-Maxwellian" EEPFs is also observed. The temperature of low energy electron group ( Tb u l k) shows significant increase with helium addition, while the temperature of tail electrons ( Tt a i l) increases smoothly as compared to ( Tb u l k).

  6. Plasma surface kinetics studies of silicon dioxide etch process in inductively coupled fluorocarbon plasmas

    NASA Astrophysics Data System (ADS)

    Chang, Won-Seok; Yu, Dong-Hun; Cho, Deog-Gyun; Yook, Yeong-Geun; Chun, Poo-Reum; Lee, Se-Ah; Kwon, Deuk-Chul; Im, Yeon-Ho

    2013-09-01

    With continuous decrease of nanoscale design rule, plasma etching processes to form high aspect ratio contact hole still remains a challenge to overcome their inherent drawbacks such as bowing and twisted feature. Due to their complexities there still exist big gaps between current research status and predictable modeling of this process. To address this issue, we proposed a surface kinetic model of silicon nitride etch process under inductively coupled fluorocarbon plasmas. For this work, the cut-off probe and quadrapole mass spectroscopy were used for measuring electrical plasma properties, the ion and neutral radical species. Furthermore, the systematic surface analysis was performed to investigate the thickness and chemical bonding of polymer passivation layer during the etch process. The proposed semi-global surface kinetic model can consider deposition of polymer passivation layer and silicon nitride etching self-consistently. The predicted modeling results showed good agreement with experimental data. We believe that our research will provide valuable information to avoid the empirical development of plasma etching process.

  7. RELIABLE ANALYSES OF WATER BY INDUCTIVELY COUPLED PLASMA EMISSION SPECTROSCOPY. ANALYTICAL CHEMISTRY BRANCH

    EPA Science Inventory

    Reduction of stray light in the inductively coupled plasma emission spectrometer (ICPES) has greatly increased its reliability as a technique for the multielemental analysis of water. Because of interferences introduced by matrix elements, reliable analysis of some less-sensitive...

  8. Examination of aluminium and zinc plasmas from an inductive furnace by spectroscopy

    NASA Astrophysics Data System (ADS)

    Burm, K. T. A. L.; Burm

    2013-02-01

    The production of aluminium and zinc plasmas for the deposition of coatings upon steel strip is monitored by optical emission spectroscopy measurements. The plasma is created from an inductive source. The atom and the ion densities as well as the electron temperature are obtained such that the plasma can be characterized. It will be shown that the obtained plasmas are typically highly ionized and deviate from thermal equilibrium.

  9. Design and Testing of a Small Inductive Pulsed Plasma Thruster

    NASA Technical Reports Server (NTRS)

    Martin, Adam K.; Eskridge, Richard H.; Dominguez, Alexandra; Polzin, Kurt A.; Riley, Daniel P.; Kimberlin, Adam C.

    2015-01-01

    The design and testing of a small inductive pulsed plasma thruster (IPPT), shown in Fig. 1 with all the major subsystems required for a thruster of this kind are described. Thrust measurements and imaging of the device operated in rep-rated mode are presented to quantify the performance envelope of the device. The small IPPT described in this paper was designed to serve as a test-bed for the pulsed gas-valves and solid-state switches required for a IPPTs. A modular design approach was used to permit future modifications and upgrades. The thruster consists of the following sub-systems: a) a multi-turn, spiral-wound acceleration coil (27 cm o.d., 10 cm i.d.) driven by a 10 microFarad capacitor and switched with a high-voltage thyristor, b) a fast pulsed gas-valve, and c.) a glow-discharge pre-ionizer (PI) circuit. The acceleration-coil circuit may be operated at voltages up to 4 kV (the thyristor limit is 4.5 kV). The device may be operated at rep-rates up to 30 Hz with the present gas-valve. Thrust measurements and imaging of the device operated in rep-rated mode will be presented. The pre-ionizer consists of a 0.3 microFarad capacitor charged to 4 kV and connected to two annular stainless-steel electrodes bounding the area of the coil-face. The 4 kV potential is held across them and when the gas is puffed in over the coil, the PI circuit is completed, and a plasma is formed. Even at the less than optimal base-pressure in the chamber (approximately 5 × 10(exp -4) torr), the PI held-off the applied voltage, and only discharged upon command. For a capacitor charge of 2 kV the peak coil current is 4.1 kA, and during this pulse a very bright discharge (much brighter than from the PI alone) was observed (see Fig. 2). Interestingly, for discharges at this charge voltage the PI was not required as the current rise rate, dI/dt, of the coil itself was sufficient to ionize the gas.

  10. Determination of elemental content off rocks by laser ablation inductively coupled plasma mass spectrometry

    USGS Publications Warehouse

    Lichte, F.E.

    1995-01-01

    A new method of analysis for rocks and soils is presented using laser ablation inductively coupled plasma mass spectrometry. It is based on a lithium borate fusion and the free-running mode of a Nd/YAG laser. An Ar/N2 sample gas improves sensitivity 7 ?? for most elements. Sixty-three elements are characterized for the fusion, and 49 elements can be quantified. Internal standards and isotopic spikes ensure accurate results. Limits of detection are 0.01 ??g/g for many trace elements. Accuracy approaches 5% for all elements. A new quality assurance procedure is presented that uses fundamental parameters to test relative response factors for the calibration.

  11. The immune tolerance induction (ITI) dose debate: does the International ITI Study provide a clearer picture?

    PubMed

    Ettingshausen, C Escuriola; Kreuz, W

    2013-01-01

    Among the proposed predictors for immune tolerance induction (ITI) outcome, the therapeutic regimen - specifically the dose and frequency of administered factor VIII (FVIII) as well as FVIII product type - is intensely debated. Are there any advantages for low-dose regimens (50 IU FVIII kg(-1) three times a week) over high-dose regimens (200 IU FVIII kg day(-1)) or vice versa? Are von Willebrand factor (VWF)-containing plasma-derived concentrates superior to recombinant FVIII concentrates for tolerance induction? A review of the available literature indicates that patients with good prognostic factors can achieve success with either low-dose or high-dose ITI regimens. Retrospective data suggest that patient characteristics such as maximum historical inhibitor titres and pre-ITI inhibitor titres are better predictors of treatment success than dose. Results of the prospective International ITI Study have recently become available. In inhibitor patients with good prognosis, success rates were similar between low-dose (50 IU FVIII kg(-1) three times a week) and high-dose (200 IU FVIII kg(-1) daily) regimens. However, patients receiving low-dose ITI took longer to achieve various ITI milestones and had a significantly higher bleed rate per month compared with the high-dose group (0.62 vs. 0.28; P = 0.00024), findings with important clinical implications. Inhibitor patients with poor prognostic features should be treated with a high-dose protocol. This conclusion is supported by a meta-analysis of the International Immune Tolerance Registry and North American Immune Tolerance Registry and by data from Germany showing good success rates with the high-dose, high-frequency Bonn protocol in poor prognosis patients. Type of concentrate also appears to have an influence on ITI success rates in this patient subgroup, with evidence suggesting an advantage for VWF-containing plasma-derived FVIII concentrates over recombinant or VWF-free concentrates. The ongoing prospective

  12. Deposition Of Materials Using A Simple Planar Coil Radio Frequency Inductively Coupled Plasma System

    SciTech Connect

    Ng, K. H.; Wong, C. S.; Yap, S. L.; Gan, S. N.

    2009-07-07

    A planar coil RF inductively coupled plasma (PC-RFICP) systems is set up for the purpose of thin film deposition. The system is powered by a 13.56 MHz, 550 W, 50 OMEGA RF generator. The RF power is transferred to the plasma via a planar induction coil. The impedance matching unit consists of an air core step-down transformer and a tunable vacuum capacitor. This system is used for the plasma enhanced chemical vapor deposition (PECVD) of diamond-like carbon (DLC) film on silicon substrate, and hydrogenated amorphous carbon (a-C:H) film.

  13. Thrust Stand Measurements Using Alternative Propellants in the Microwave Assisted Discharge Inductive Plasma Accelerator

    NASA Technical Reports Server (NTRS)

    Hallock, Ashley K.; Polzin, Kurt A.

    2011-01-01

    Storable propellants (for example water, ammonia, and hydrazine) are attractive for deep space propulsion due to their naturally high density at ambient interplanetary conditions, which obviates the need for a cryogenic/venting system. Water in particular is attractive due to its ease of handling and availability both terrestrially and extra-terrestrially. While many storable propellants are reactive and corrosive, a propulsion scheme where the propellant is insulated from vulnerable (e.g. metallic) sections of the assembly would be well-suited to process these otherwise incompatible propellants. Pulsed inductive plasma thrusters meet this criterion because they can be operated without direct propellant-electrode interaction. During operation of these devices, electrical energy is capacitively stored and then discharged through an inductive coil creating a time-varying current in the coil that interacts with a plasma covering the face of the coil to induce a plasma current. Propellant is accelerated and expelled at a high exhaust velocity (O(10-100 km/s)) by the Lorentz body force arising from the interaction of the magnetic field and the induced plasma current. While this class of thruster mitigates the life-limiting issues associated with electrode erosion, many pulsed inductive plasma thrusters require high pulse energies to inductively ionize propellant. The Microwave Assisted Discharge Inductive Plasma Accelerator (MAD-IPA) is a pulsed inductive plasma thruster that addressees this issue by partially ionizing propellant inside a conical inductive coil before the main current pulse via an electron cyclotron resonance (ECR) discharge. The ECR plasma is produced using microwaves and a static magnetic field from a set of permanent magnets arranged to create a thin resonance region along the inner surface of the coil, restricting plasma formation, and in turn current sheet formation, to a region where the magnetic coupling between the plasma and the theta

  14. Investigation of Non-inductive Plasma Current Start-up by RF on QUEST

    NASA Astrophysics Data System (ADS)

    Ishiguro, Masaki; Hanada, Kazuaki; Liu, Hiqing; Ogata, Ryota; Isobe, Mitsutaka; Tashima, Saya; Zushi, Hideki; Sato, Khonosuke; Fujisawa, Akihide; Nakamura, Kazuo; Idei, Hiroshi; Sakamoto, Mizuki; Hasegawa, Makoto; Takase, Yuichi; Maekawa, Takashi; Kishimoto, Yasuaki; Mitarai, Osamu; Kawasaki, Shoji; Nakashima, Hisatoshi; Higashijima, Aki

    2014-05-01

    Formations of a closed flux surface (CFS) on QUEST are achieved by fully non-inductive current start-up driven by RF, which is 8.2GHz in frequency and more than 40kW in power. It found that appropriate magnetic configuration with positive n-index and reduction of particle recycling was crucial to achieve the non-inductive plasma current start-up (PCS) successfully. Especially the controllability of particle recycling should be improved by wall conditioning based on successive plasma production and wall cleaning with electron cyclotron resonance heating (ECR) plasmas induced by RF in frequency of 2.45GHz.

  15. Supporting First Year Alternatively Certified Urban and Rural Intern Teachers through a Multicomponent Distance Induction Program

    ERIC Educational Resources Information Center

    Gresko, Jennifer A.

    2013-01-01

    The pathway for entering the K-12 classroom as a teacher varies compared to what was once the traditional model of teacher preparation. In this mixed-methods action research study, I explore supporting first year alternatively certified urban and rural intern teachers through a multicomponent distance induction program. The induction model in this…

  16. Spatial measurements of electron energy distribution and plasma parameters in a weakly magnetized inductive discharge

    SciTech Connect

    Kim, Young-Do; Lee, Young-Kwang; Lee, Hyo-Chang; Chung, Chin-Wook

    2013-02-15

    Spatial characteristics of plasma parameters such as electron temperature, plasma density, plasma potential, and electron energy distribution (EED) were studied in inductively coupled plasma with an axial dc magnetic field. With dc magnetic field, the measured EEDs in the total electron energy scale are spatially coincided except cutting of the low electron energy part indicating the conserved non-local electron kinetics in an axial direction, even though the dc magnetic field is applied. Spatial distributions of the plasma densities at axial positions have almost same trends with various magnetic field strengths. We also discuss the reduction of the ambipolar potential along the axial direction as the applied magnetic field increased.

  17. Generation Of High Non-inductive Plasma Current Fraction H-mode Discharges By High-harmonic Last Wave Heating In The National Spherical Torus Experiment

    SciTech Connect

    Taylor, G; Kessel, C E; LeBlanc, B P; Mueller, D; Phillips, D K; Valeo, E J; Wilson, J R; Ryan, P M; Bonoli, P T; Wright, J C

    2012-02-13

    1.4 MW of 30 MHz high-harmonic fast wave (HHFW) heating, with current drive antenna phasing, has generated a Ip = 300kA, BT (0) = 0.55T deuterium H-mode plasma in the National Spherical Torus Experiment that has a non-inductive plasma current fraction, fNI = 0.7-1. Seventy-five percent of the non-inductive current was generated inside an internal transport barrier that formed at a normalized minor radius, r/a {approx} 0.4 . Three quarters of the non-inductive current was bootstrap current and the remaining non-inductive current was generated directly by HHFW power inside r/a {approx} 0.2.

  18. Comparative Study of Plasma Parameters in Magnetic Pole Enhanced Inductively Coupled Argon Plasmas

    NASA Astrophysics Data System (ADS)

    F., Jan; W. Khan, A.; Saeed, A.; Zakaullah, M.

    2013-04-01

    Langmuir probe measurements of radio frequency (RF) magnetic pole enhanced inductively coupled (MaPE-ICP) argon plasma were accomplished to obtain the electron number densities and electron temperatures. The measurements were carried out with a fixed RF frequency of 13.56 MHz in a pressure range of 7.5 mTorr to 75 mTorr at an applied RF power of 10 W and 100 W. These results are compared with a global (volume average) model. The results show good agreement between theoretical and experimental measurements. The electron number density shows an increasing trend with both RF power and pressure while the electron temperature shows decreasing trend as the pressure increases. The difference in the plasma potential and floating potential as a function of electron temperature measured from the electrical probe and that obtained theoretically shows a linear relation with a small difference in the coefficient of proportionality. The intensity of the emission line at 750.4 nm due to 2p1 → 1s2 (Paschen's notation) transition closely follows the variation of ne with RF power and filling gas pressure. Measured electron energy probability function (EEPF) shows that electron occupation changes mostly in the high-energy tail, which highlights close similarity of 750.4 nm argon line to ne.

  19. [Analysis of Trace Inorganic Elements in Castor Oil by Inductively Coupled Plasma Mass Spectrometry].

    PubMed

    Li, Tan-ping; Xie, Hua-lin; Nie, Xi-du

    2015-10-01

    A method for the determination of Na, Mg, Si, P, K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Sr, Mo, Cd, Hg and Pb in castor oil after direct dilution with ethanol by inductively coupled plasma mass spectrometry (ICP-MS) was established. The sample was diluted by ethanol before ICP-MS determination. The condensation and deposition of high concentrations of carbon in mass cone interface and ion lens, which will decrease the sensitivity of element analysis, were avoided effectively by introducing O2 to plasma. The mass spectral interferences were eliminated by octopole reaction system (ORS). The matrix effects were calibrated to using Sc, Ge, Rh and Ir as internal standard elements. Au standard solution, which could form amalgam alloy with Hg, was dropped to eliminate the memory effect of Hg. The results show that the correlation coefficient for analyte is no less than 0.999 5, the detection limits is in the range of 0.06 - 20.1 ng x L(-1), the recovery is in the range of 990.4% - 110.2%, and the RSD is less than 4.8%. This method was very fast, simple and accurate to simultaneously analyze multi-elements in castor oil. PMID:26904837

  20. Energy deposition into heavy gas plasma via pulsed inductive theta-pinch

    NASA Astrophysics Data System (ADS)

    Pahl, Ryan Alan

    The objective of this research is to study the formation processes of a pulsed inductive plasma using heavy gases, specifically the coupling of stored capacitive energy into plasma via formation in a theta pinch coil. To aid in this research, the Missouri Plasmoid Experiment Mk. I (and later Mk. II) was created. In the first paper, the construction of differential magnetic field probes are discussed. The effects of calibration setup on B-dot probes is studied using a Helmholtz coil driven by a vector network analyzer and a pulsed-power system. Calibration in a pulsed-power environment yielded calibration factors at least 9.7% less than the vector network analyzer. In the second paper, energy deposition into various gases using a pulsed inductive test article is investigated. Experimental data are combined with a series RLC model to quantify the energy loss associated with plasma formation in Argon, Hydrogen, and Xenon at pressures from 10-100 mTorr. Plasma resistance is found to vary from 25.8-51.6 mΩ and plasma inductance varies from 41.3--47.0 nH. The greatest amount of initial capacitively stored energy that could be transferred to the plasma was 6.4 J (8.1%) of the initial 79.2 +/- 0.1 J. In the third paper, the effects of a DC preionization source on plasma formation energy is studied. The preionization source radial location is found to have negligible impact on plasma formation repeatability while voltage is found to be critical at low pressures. Without preionization, plasma formation was not possible. At 20 mTorr, 0.20 W of power was sufficient to stabilize plasma formation about the first zero-crossing of the discharge current. Increasing power to 1.49 W increased inductively coupled energy by 39%. At 200 mTorr, 4.3 mW was sufficient to produce repeatable plasma properties.

  1. Performance Effects of Adding a Parallel Capacitor to a Pulse Inductive Plasma Accelerator Powertrain

    NASA Technical Reports Server (NTRS)

    Polzin, Kurt A.; Sivak, Amy D.; Balla, Joseph V.

    2011-01-01

    Pulsed inductive plasma accelerators are electrodeless space propulsion devices where a capacitor is charged to an initial voltage and then discharged through a coil as a high-current pulse that inductively couples energy into the propellant. The field produced by this pulse ionizes the propellant, producing a plasma near the face of the coil. Once a plasma is formed if can be accelerated and expelled at a high exhaust velocity by the Lorentz force arising from the interaction of an induced plasma current and the magnetic field. While there are many coil geometries that can be employed to inductively accelerate a plasma, in this paper the discussion is limit to planar geometries where the coil take the shape of a flat spiral. A recent review of the developmental history of planar-geometry pulsed inductive thrusters can be found in Ref. [1]. Two concepts that have employed this geometry are the Pulsed Inductive Thruster (PIT) and the Faraday Accelerator with Radio-frequency Assisted Discharge (FARAD).

  2. Local cooling, plasma reheating and thermal pinching induced by single aerosol droplets injected into an inductively coupled plasma

    NASA Astrophysics Data System (ADS)

    Chan, George C.-Y.; Hieftje, Gary M.

    2016-07-01

    The injection of a single micrometer-sized droplet into an analytical inductively coupled plasma (ICP) perturbs the plasma and involves three sequential effects: local cooling, thermal pinching and plasma reheating. Time-resolved two-dimensional monochromatic imaging of the load-coil region of an ICP was used to monitor this sequence of plasma perturbations. When a microdroplet enters the plasma, it acts as a local heat sink and cools the nearby plasma region. The cooling effect is considered local, although the cooling volume can be large and extends 6 mm from the physical location of the vaporizing droplet. The liberated hydrogen, from decomposition of water, causes a thermal pinch effect by increasing the thermal conductivity of the bulk plasma and accelerating heat loss at the plasma periphery. As a response to the heat loss, the plasma shrinks in size, which increases its power density. Plasma shrinkage starts around the same time when the microdroplet enters the plasma and lasts at least 2 ms after the droplet leaves the load-coil region. Once the vaporizing droplet passes through a particular plasma volume, that volume is reheated to an even higher temperature than under steady-state conditions. Because of the opposing effects of plasma cooling and reheating, the plasma conditions are different upstream (downward) and downstream (upward) from a vaporizing droplet - cooling dominates the downstream region whereas reheating controls in the upstream domain. The boundary between the local cooling and reheating zones is sharp and is only ~ 1 mm thick. The reheating effect persists a relatively long time in the plasma, at least up to 4 ms after the droplet moves out of the load-coil region. The restoration of plasma equilibrium after the perturbation induced by microdroplet injection is slow. Microdroplet injection also induces a momentary change in plasma impedance, and the impedance change was found to correlate qualitatively with the different stages of plasma

  3. Ion flux and ion distribution function measurements in synchronously pulsed inductively coupled plasmas

    SciTech Connect

    Brihoum, Melisa; Cunge, Gilles; Darnon, Maxime; Joubert, Olivier; Gahan, David; Braithwaite, Nicholas St. J.

    2013-03-15

    Changes in the ion flux and the time-averaged ion distribution functions are reported for pulsed, inductively coupled RF plasmas (ICPs) operated over a range of duty cycles. For helium and argon plasmas, the ion flux increases rapidly after the start of the RF pulse and after about 50 {mu}s reaches the same steady state value as that in continuous ICPs. Therefore, when the plasma is pulsed at 1 kHz, the ion flux during the pulse has a value that is almost independent of the duty cycle. By contrast, in molecular electronegative chlorine/chlorosilane plasmas, the ion flux during the pulse reaches a steady state value that depends strongly on the duty cycle. This is because both the plasma chemistry and the electronegativity depend on the duty cycle. As a result, the ion flux is 15 times smaller in a pulsed 10% duty cycle plasma than in the continuous wave (CW) plasma. The consequence is that for a given synchronous RF biasing of a wafer-chuck, the ion energy is much higher in the pulsed plasma than it is in the CW plasma of chlorine/chlorosilane. Under these conditions, the wafer is bombarded by a low flux of very energetic ions, very much as it would in a low density, capacitively coupled plasma. Therefore, one can extend the operating range of ICPs through synchronous pulsing of the inductive excitation and capacitive chuck-bias, offering new means by which to control plasma etching.

  4. Flow dynamics and magnetic induction in the von-Kármán plasma experiment

    NASA Astrophysics Data System (ADS)

    Plihon, N.; Bousselin, G.; Palermo, F.; Morales, J.; Bos, W. J. T.; Godeferd, F.; Bourgoin, M.; Pinton, J.-F.; Moulin, M.; Aanesland, A.

    2015-01-01

    The von-Kármán plasma experiment is a novel versatile experimental device designed to explore the dynamics of basic magnetic induction processes and the dynamics of flows driven in weakly magnetized plasmas. A high-density plasma column (1016-1019 particles. m-3) is created by two radio-frequency plasma sources located at each end of a 1 m long linear device. Flows are driven through J × B azimuthal torques created from independently controlled emissive cathodes. The device has been designed such that magnetic induction processes and turbulent plasma dynamics can be studied from a variety of time-averaged axisymmetric flows in a cylinder. MHD simulations implementing volume-penalization support the experimental development to design the most efficient flow-driving schemes and understand the flow dynamics. Preliminary experimental results show that a rotating motion of up to nearly 1 km/s is controlled by the J × B azimuthal torque.

  5. Surface modification of polypropylene separators in lithium-ion batteries using inductively coupled plasma treatment.

    PubMed

    Son, Jinyoung; Kim, Min-Sik; Lee, Hyun Woo; Yu, Jong-Sung; Kwon, Kwang-Ho

    2014-12-01

    We describe herein an improvement in the surface wettability of plasma-treated separators for use in lithium-ion batteries. We treated the separators with an O2/Ar inductively coupled plasma to increase their surface energy. The plasma treatment on the separator and plasma diagnostic experiments were performed in an inductively coupled plasma (ICP) reactor. The fraction of Ar in the O2/Ar plasma was changed from 0% to 100%. The plasma diagnostics were performed using optical emission spectroscopy and a double Langmuir probe. To confirm the morphological change of the separator membrane by the plasma treatment, we used the scanning electron microscopy. The surface energy measurements were performed using the drop method. We found that the plasma treatment transformed the separator from a hydrophobic membrane to a hydrophilic one, thereby achieving high separator wettability. After the treatment of the separators with O2/Ar plasma, the batteries exhibited better cycle performance and rate capacity than those employing the untreated ones. PMID:25971067

  6. Effect of a Second, Parallel Capacitor on the Performance of a Pulse Inductive Plasma Thruster

    NASA Technical Reports Server (NTRS)

    Polzin, Kurt A.; Balla, Joseph V.

    2010-01-01

    Pulsed inductive plasma accelerators are electrodeless space propulsion devices where a capacitor is charged to an initial voltage and is then discharged through an inductive coil that couples energy into the propellant, ionizing and accelerating it to produce thrust. A model that employs a set of circuit equations (as illustrated in Fig. 1a) coupled to a one-dimensional momentum equation has been previously used by Lovberg and Dailey [1] and Polzin et al. [2-4] to model the plasma acceleration process in pulsed inductive thrusters. In this paper an extra capacitor, inductor, and resistor are added to the system in the manner illustrated in the schematic shown in Fig. 1b. If the second capacitor has a smaller value than the initially charged capacitor, it can serve to increase the current rise rate through the inductive coil. Increasing the current rise rate should serve to better ionize the propellant. The equation of motion is solved to find the effect of an increased current rise rate on the acceleration process. We examine the tradeoffs between enhancing the breakdown process (increasing current rise rate) and altering the plasma acceleration process. These results provide insight into the performance of modified circuits in an inductive thruster, revealing how this design permutation can affect an inductive thruster's performance.

  7. A comprehensive study of different gases in inductively coupled plasma torch operating at one atmosphere

    SciTech Connect

    Punjabi, Sangeeta B.; Joshi, N. K.; Mangalvedekar, H. A.; Lande, B. K.; Das, A. K.; Kothari, D. C.

    2012-01-15

    A numerical study is done to understand the possible operating regimes of RF-ICP torch (3 MHz, 50 kW) using different gases for plasma formation at atmospheric pressure. A two dimensional numerical simulation of RF-ICP torch using argon, nitrogen, oxygen, and air as plasma gas has been investigated using computational fluid dynamic (CFD) software fluent{sup (c)}. The operating parameters varied here are central gas flow, sheath gas flow, RF-power dissipated in plasma, and plasma gas. The temperature contours, flow field, axial, and radial velocity profiles were investigated under different operating conditions. The plasma resistance, inductance of the torch, and the heat distribution for various plasma gases have also been investigated. The plasma impedance of ICP torch varies with different operating parameters and plays an important role for RF oscillator design and power coupling. These studies will be useful to decide the design criteria for ICP torches required for different material processing applications.

  8. Neutral depletion in inductively coupled plasmas using hybrid-type direct simulation Monte Carlo

    SciTech Connect

    Shimada, Masashi; Tynan, George R.; Cattolica, Robert

    2008-02-01

    Neutral and ion transport phenomena were simulated by a hybrid-type direct simulation Monte Carlo (DSMC) method for a one-dimensional (1D) electrostatic plasma in Ar/N{sub 2} mixtures to identify the mechanism of neutral depletion. The results show that gas heating and pressure balance are the main mechanisms of neutral depletion in an inductively coupled plasma. When plasma pressure becomes comparable to neutral pressure in high density plasma sources (T{sub e}{approx}2-5 eV, n{sub e}{approx}10{sup 11}-10{sup 12} cm{sup -3}), the total pressure (neutral pressure and plasma pressure) is conserved. Therefore, the finite plasma pressure (mainly electron pressure) reduces the neutral pressure. Neutrals collide with ions that have been accelerated by the ambipolar electric field and with Franck-Condon dissociated atoms, resulting in gas heating. Significant neutral depletion (up to 90%) is found at the typical condition of inductively coupled plasma process reactors. The resulting neutral depletion enhances the plasma transport to the surrounding wall, increases the particle loss, and decreases the plasma density.

  9. 3-Dimensional Modeling of Capacitively and Inductively Coupled Plasma Etching Systems

    NASA Astrophysics Data System (ADS)

    Rauf, Shahid

    2008-10-01

    Low temperature plasmas are widely used for thin film etching during micro and nano-electronic device fabrication. Fluid and hybrid plasma models were developed 15-20 years ago to understand the fundamentals of these plasmas and plasma etching. These models have significantly evolved since then, and are now a major tool used for new plasma hardware design and problem resolution. Plasma etching is a complex physical phenomenon, where inter-coupled plasma, electromagnetic, fluid dynamics, and thermal effects all have a major influence. The next frontier in the evolution of fluid-based plasma models is where these models are able to self-consistently treat the inter-coupling of plasma physics with fluid dynamics, electromagnetics, heat transfer and magnetostatics. We describe one such model in this paper and illustrate its use in solving engineering problems of interest for next generation plasma etcher design. Our 3-dimensional plasma model includes the full set of Maxwell equations, transport equations for all charged and neutral species in the plasma, the Navier-Stokes equation for fluid flow, and Kirchhoff's equations for the lumped external circuit. This model also includes Monte Carlo based kinetic models for secondary electrons and stochastic heating, and can take account of plasma chemistry. This modeling formalism allows us to self-consistently treat the dynamics in commercial inductively and capacitively coupled plasma etching reactors with realistic plasma chemistries, magnetic fields, and reactor geometries. We are also able to investigate the influence of the distributed electromagnetic circuit at very high frequencies (VHF) on the plasma dynamics. The model is used to assess the impact of azimuthal asymmetries in plasma reactor design (e.g., off-center pump, 3D magnetic field, slit valve, flow restrictor) on plasma characteristics at frequencies from 2 -- 180 MHz. With Jason Kenney, Ankur Agarwal, Ajit Balakrishna, Kallol Bera, and Ken Collins.

  10. Self-consistent multidimensional electron kinetic model for inductively coupled plasma sources

    NASA Astrophysics Data System (ADS)

    Dai, Fa Foster

    Inductively coupled plasma (ICP) sources have received increasing interest in microelectronics fabrication and lighting industry. In 2-D configuration space (r, z) and 2-D velocity domain (νθ,νz), a self- consistent electron kinetic analytic model is developed for various ICP sources. The electromagnetic (EM) model is established based on modal analysis, while the kinetic analysis gives the perturbed Maxwellian distribution of electrons by solving Boltzmann-Vlasov equation. The self- consistent algorithm combines the EM model and the kinetic analysis by updating their results consistently until the solution converges. The closed-form solutions in the analytical model provide rigorous and fast computing for the EM fields and the electron kinetic behavior. The kinetic analysis shows that the RF energy in an ICP source is extracted by a collisionless dissipation mechanism, if the electron thermovelocity is close to the RF phase velocities. A criterion for collisionless damping is thus given based on the analytic solutions. To achieve uniformly distributed plasma for plasma processing, we propose a novel discharge structure with both planar and vertical coil excitations. The theoretical results demonstrate improved uniformity for the excited azimuthal E-field in the chamber. Non-monotonic spatial decay in electric field and space current distributions was recently observed in weakly- collisional plasmas. The anomalous skin effect is found to be responsible for this phenomenon. The proposed model successfully models the non-monotonic spatial decay effect and achieves good agreements with the measurements for different applied RF powers. The proposed analytical model is compared with other theoretical models and different experimental measurements. The developed model is also applied to two kinds of ICP discharges used for electrodeless light sources. One structure uses a vertical internal coil antenna to excite plasmas and another has a metal shield to prevent the

  11. Simulations of ponderomotive effects in inductively coupled plasmas

    SciTech Connect

    Sydorenko, D.Y.; Smolyakov, A.I.; Tyshetskiy, Y.O.; Godyak, V.A.

    2005-03-01

    The electromagnetic quasineutral particle-in-cell code, simulating interaction of a plane electromagnetic wave with a plasma slab, is developed. The code is used to study the ponderomotive effects in a plasma with a finite temperature. Simulations in linear regime show the strong thermal reduction of the ponderomotive force, which is in a good agreement with the linear analytical theory. It is found that in the essentially nonlinear regime, when the electron trajectories are strongly modified, the amplitude of the ponderomotive force increases compared to the linear case, but remains lower than the classical cold plasma value. The transition from nonlinear to linear regime as a function of the amplitude of the driving electromagnetic field is investigated.

  12. Modelling of an inductively coupled plasma torch with argon at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Bahouh, Hanene; Rebiai, Saida; Rochette, David; Vacher, Damien; Dudeck, Michel

    2014-05-01

    A fluid dynamic model is used to simulate the electromagnetic field, fluid flow and heat transfer in an inductively coupled plasma torch working at atmospheric pressure for argon plasma. The numerical simulation is carried out by using the finite element method based on COMSOL software. The two-dimensional profiles of the electric field, temperature, velocity and charged particle densities are demonstrated inside the discharge region. These numerical results are obtained for a fixed flow rate, frequency and electric power.

  13. Synthesis of carbon onionlike nanostructures from methane in plasma flow of induction plasmatron

    NASA Astrophysics Data System (ADS)

    Anchukov, K. E.; Zalogin, G. N.; Krasil'nikov, A. V.; Popov, M. Yu.; Kul'nitskii, B. A.

    2015-11-01

    The results of synthesis of carbon onionlike nanostructures from methane in plasma flow of inert gas (argon) generated in induction high-frequency plasmatron are considered and discussed. Carbon vapor obtained via dissociation of methane in plasma flow was condensed on copper substrates placed in a working chamber of the setup. The content of the synthesized soot was analyzed using scanning and transmission electron microscopy. As a result of the performed experiments, carbon onionlike structures with 20- to 100-nm sizes were obtained.

  14. Energetic electron avalanches and mode transitions in planar inductively coupled radio-frequency driven plasmas operated in oxygen

    SciTech Connect

    Zaka-ul-Islam, M.; Niemi, K.; Gans, T.; O'Connell, D.

    2011-07-25

    Space and phase resolved optical emission spectroscopic measurements reveal that in certain parameter regimes, inductively coupled radio-frequency driven plasmas exhibit three distinct operation modes. At low powers, the plasma operates as an alpha-mode capacitively coupled plasma driven through the dynamics of the plasma boundary sheath potential in front of the antenna. At high powers, the plasma operates in inductive mode sustained through induced electric fields due to the time varying currents and associated magnetic fields from the antenna. At intermediate powers, close to the often observed capacitive to inductive (E-H) transition regime, energetic electron avalanches are identified to play a significant role in plasma sustainment, similar to gamma-mode capacitively coupled plasmas. These energetic electrons traverse the whole plasma gap, potentially influencing plasma surface interactions as exploited in technological applications.

  15. Ideal internal kink modes in a differentially rotating cylindrical plasma

    SciTech Connect

    Mikhailovskii, A. B.; Lominadze, J. G.; Galvao, R. M. O.; Churikov, A. P.; Erokhin, N. N.; Pustovitov, V. D.; Konovalov, S. V.; Smolyakov, A. I.; Tsypin, V. S.

    2008-07-15

    The Velikhov effect leading to magnetorotational instability (MRI) is incorporated into the theory of ideal internal kink modes in a differentially rotating cylindrical plasma column. It is shown that this effect can play a stabilizing role for suitably organized plasma rotation profiles, leading to suppression of MHD (magnetohydrodynamic) instabilities in magnetic confinement systems. The role of this effect in the problem of the Suydam and the m = 1 internal kink modes is elucidated, where m is the poloidal mode number.

  16. INDUCTIVELY COUPLED PLASMA-ATOMIC EMISSION SPECTROMETRIC ANALYSIS OF ENVIRONMENTAL SAMPLES USING ULTRASONIC NEBULIZATION

    EPA Science Inventory

    Ultrasonic and pneumatic nebulizers used in inductively coupled plasma-atomic emission spectrometry (ICP-AES) are compared in the analysis of standard materials and environmental samples. Results verify that ICP-AES with ultrasonic nebulization is capable of lower detection limit...

  17. Determination of Arsenic in Sinus Wash and Tap Water by Inductively Coupled Plasma-Mass Spectrometry

    ERIC Educational Resources Information Center

    Donnell, Anna M.; Nahan, Keaton; Holloway, Dawone; Vonderheide, Anne P.

    2016-01-01

    Arsenic is a toxic element to which humans are primarily exposed through food and water; it occurs as a result of human activities and naturally from the earth's crust. An experiment was developed for a senior level analytical laboratory utilizing an Inductively Coupled Plasma-Mass Spectrometer (ICP-MS) for the analysis of arsenic in household…

  18. INTERLABORATORY STUDY OF INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION SPECTROSCOPY METHOD 6010 AND DIGESTION METHOD 3050

    EPA Science Inventory

    The design, execution, and results of an interlaboratory study of Method 6010, 'Inductively Coupled Plasma Atomic Emission Spectroscopy,' are described. The study examined the application of the method to the analysis of solid-waste materials for 23 elements. Part of the interlab...

  19. Inductively coupled plasma-atomic emission spectroscopy: The determination of trace impurities in uranium hexafluoride

    NASA Astrophysics Data System (ADS)

    Floyd, M. A.; Morrow, R. W.; Farrar, R. B.

    An analytical method has been developed for the determination of trace impurities in high-purity uranium hexafluoride using liquid-liquid extraction of the uranium from the trace impurities followed by analysis with inductively coupled plasma-atomic emission spectroscopy. Detection limits, accuracy, and precision data are presented.

  20. ULTRASONIC NEBULIZATION AND ARSENIC VALENCE STATE CONSIDERATIONS PRIOR TO DETERMINATION VIA INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY

    EPA Science Inventory

    An ultrasonic nebulizer (USN) was utilized as a sample introduction device for an inductively coupled plasma mass spectrometer in an attempt to increase the sensitivity for As. The USN produced a valence state response difference for As. The As response was suppressed approximate...

  1. DETERMINATION OF BROMATE IN DRINKING WATERS BY ION CHROMATOGRAPHY WITH INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRIC DETECTION

    EPA Science Inventory

    Bromate is a disinfection by-product in drinking water, formed during the ozonation of source water containing bromide. An inductively coupled plasma mass spectrometer is combined with an ion chromatograph for the analysis of bromate in drinking waters. Three chromatographic colu...

  2. INDUCTIVELY COUPLED ARGON PLASMA AS AN ION SOURCE FOR MASS SPECTROMETRIC DETERMINATION OF TRACE ELEMENTS

    EPA Science Inventory

    Solution aerosols are injected into an inductively coupled argon plasma (ICP) to generate a relatively high number density of positive ions derived from elemental constituents. A small fraction of these ions is extracted through a sampling orifice into a differentially pumped vac...

  3. CAPILLARY ELECTROPHORESIS COUPLED ON-LINE WITH INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY FOR ELEMENTAL SPECIATION

    EPA Science Inventory

    A novel interface to connect a capillary electrophoresis (CE) system with an inductively coupled plasma mass spectrometric (ICPMS) detector is reported here. The interface was built using a direct injection nebulizer (DIN) system. In this interface, the CE capillary was placed co...

  4. In situ calibration of inductively coupled plasma-atomic emission and mass spectroscopy

    DOEpatents

    Braymen, Steven D.

    1996-06-11

    A method and apparatus for in situ addition calibration of an inductively coupled plasma atomic emission spectrometer or mass spectrometer using a precision gas metering valve to introduce a volatile calibration gas of an element of interest directly into an aerosol particle stream. The present situ calibration technique is suitable for various remote, on-site sampling systems such as laser ablation or nebulization.

  5. Atlas of atomic spectral lines of plutonium emitted by an inductively coupled plasma

    SciTech Connect

    Edelson, M.C.; DeKalb, E.L.; Winge, R.K.; Fassel, V.A.

    1986-09-01

    Optical emission spectra from high-purity Pu-242 were generated with a glovebox-enclosed inductively coupled plasma (ICP) source. Spectra covering the 2280 to 7008 Angstrom wavelength range are presented along with general commentary on ICP-Pu spectroscopy.

  6. Effects of capacitor termination to an antenna coil on the plasma parameters in a radio frequency inductively coupled plasma

    NASA Astrophysics Data System (ADS)

    Han, Duksun; Lee, Hyo-Chang; Kim, H. J.; Sin Kim, Yu; Chung, Chin-Wook; Chae, Heesun

    2013-10-01

    The effects of capacitor termination to a solenoidal antenna coil on the plasma parameters, such as the plasma density, the electron temperature, the electron energy distribution function and the plasma potential, are studied in an Ar or O2/N2 gas mixture inductively coupled plasma (ICP). As the capacitance is varied from tens to hundreds of pF, the plasma parameters change significantly. When the reactance of the capacitor is half that of the antenna, there is a resonance condition where the electrostatic coupling between the antenna coil and the chamber wall is effectively suppressed. The plasma density is maximal, while the electron temperature and the plasma potential are minimal under this resonance condition. This result shows that the ICP generated by the antenna coil with capacitor termination can be applied to a plasma process that requires high plasma density and low ion damage. The ashing process of a photoresistor by the ICP source with capacitor termination is also performed in this study and it is found that the ashing rate is enhanced under the resonance condition compared with the non-resonance condition.

  7. Sulfur-based absolute quantification of proteins using isotope dilution inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Lee, Hyun-Seok; Heun Kim, Sook; Jeong, Ji-Seon; Lee, Yong-Moon; Yim, Yong-Hyeon

    2015-10-01

    An element-based reductive approach provides an effective means of realizing International System of Units (SI) traceability for high-purity biological standards. Here, we develop an absolute protein quantification method using double isotope dilution (ID) inductively coupled plasma mass spectrometry (ICP-MS) combined with microwave-assisted acid digestion for the first time. We validated the method and applied it to certify the candidate protein certified reference material (CRM) of human growth hormone (hGH). The concentration of hGH was determined by analysing the total amount of sulfur in hGH. Next, the size-exclusion chromatography method was used with ICP-MS to characterize and quantify sulfur-containing impurities. By subtracting the contribution of sulfur-containing impurities from the total sulfur content in the hGH CRM, we obtained a SI-traceable certification value. The quantification result obtained with the present method based on sulfur analysis was in excellent agreement with the result determined via a well-established protein quantification method based on amino acid analysis using conventional acid hydrolysis combined with an ID liquid chromatography-tandem mass spectrometry. The element-based protein quantification method developed here can be generally used for SI-traceable absolute quantification of proteins, especially pure-protein standards.

  8. Quantitative images of metals in plant tissues measured by laser ablation inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Becker, J. S.; Dietrich, R. C.; Matusch, A.; Pozebon, D.; Dressler, V. L.

    2008-11-01

    Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used for quantitative imaging of toxic and essential elements in thin sections (thickness of 30 or 40 μm) of tobacco plant tissues. Two-dimensional images of Mg, Fe, Mn, Zn, Cu, Cd, Rh, Pt and Pb in leaves, shoots and roots of tobacco were produced. Sections of the plant tissues (fixed onto glass slides) were scanned by a focused beam of a Nd:YAG laser in a laser ablation chamber. The ablated material was transported with argon as carrier gas to the ICP ion source at a quadrupole ICP-MS instrument. Ion intensities of the investigated elements were measured together with 13C +, 33S + and 34S + within the entire plant tissue section. Matrix matching standards (prepared using powder of dried tobacco leaves) were used to constitute calibration curves, whereas the regression coefficient of the attained calibration curves was typically 0.99. The variability of LA-ICP-MS process, sample heterogeneity and water content in the sample were corrected by using 13C + as internal standard. Quantitative imaging of the selected elements revealed their inhomogeneous distribution in leaves, shoots and roots.

  9. [Determination of Heavy Metal Elements in Diatomite Filter Aid by Inductively Coupled Plasma Mass Spectrometry].

    PubMed

    Nie, Xi-du; Fu, Liang

    2015-11-01

    This study established a method for determining Be, Cr, Ni, As, Cd, Sb, Sn, Tl, Hg and Pb, total 10 heavy metals in diatomite filter aid. The diatomite filter aid was digested by using the mixture acid of HNO₃ + HF+ H₃PO₄ in microwave system, 10 heavy metals elements were determined by inductively coupled plasma mass spectrometry (ICP-MS). The interferences of mass spectrometry caused by the high silicon substrate were optimized, first the equipment parameters and isotopes of test metals were selected to eliminate these interferences, the methane was selected as reactant gas, and the mass spectral interferences were eliminated by dynamic reaction cell (DRC). Li, Sc, Y, In and Bi were selected as the internal standard elements to correct the interferences caused by matrix and the drift of sensitivity. The results show that the detection limits for analyte is in the range of 3.29-15.68 ng · L⁻¹, relative standard deviations (RSD) is less than 4.62%, and the recovery is in the range of 90.71%-107.22%. The current method has some advantages such as, high sensitivity, accurate, and precision, which can be used in diatomite filter aid quality control and safety estimations. PMID:26978934

  10. Depleted uranium analysis in blood by inductively coupled plasma mass spectrometry

    USGS Publications Warehouse

    Todorov, T.I.; Xu, H.; Ejnik, J.W.; Mullick, F.G.; Squibb, K.; McDiarmid, M.A.; Centeno, J.A.

    2009-01-01

    In this study we report depleted uranium (DU) analysis in whole blood samples. Internal exposure to DU causes increased uranium levels as well as change in the uranium isotopic composition in blood specimen. For identification of DU exposure we used the 235U/238U ratio in blood samples, which ranges from 0.00725 for natural uranium to 0.002 for depleted uranium. Uranium quantification and isotopic composition analysis were performed by inductively coupled plasma mass spectrometry. For method validation we used eight spiked blood samples with known uranium concentrations and isotopic composition. The detection limit for quantification was determined to be 4 ng L-1 uranium in whole blood. The data reproduced within 1-5% RSD and an accuracy of 1-4%. In order to achieve a 235U/238U ratio range of 0.00698-0.00752% with 99.7% confidence limit a minimum whole blood uranium concentration of 60 ng L??1 was required. An additional 10 samples from a cohort of veterans exposed to DU in Gulf War I were analyzed with no knowledge of their medical history. The measured 235U/ 238U ratios in the blood samples were used to identify the presence or absence of DU exposure within this patient group. ?? 2009 The Royal Society of Chemistry.

  11. Effect of Inductive Coil Geometry on the Operating Characteristics of an Inductive Pulsed Plasma Thruster

    NASA Technical Reports Server (NTRS)

    Hallock, Ashley K.; Polzin, Kurt A.; Kimberlin, Adam C.; Perdue, Kevin A.

    2012-01-01

    Operational characteristics of two separate inductive thrusters with conical theta pinch coils of different cone angles are explored through thrust stand measurements and time- integrated, unfiltered photography. Trends in impulse bit measurements indicate that, in the present experimental configuration, the thruster with the inductive coil possessing a smaller cone angle produced larger values of thrust, in apparent contradiction to results of a previous thruster acceleration model. Areas of greater light intensity in photographs of thruster operation are assumed to qualitatively represent locations of increased current density. Light intensity is generally greater in images of the thruster with the smaller cone angle when compared to those of the thruster with the larger half cone angle for the same operating conditions. The intensity generally decreases in both thrusters for decreasing mass flow rate and capacitor voltage. The location of brightest light intensity shifts upstream for decreasing mass flow rate of propellant and downstream for decreasing applied voltage. Recognizing that there typically exists an optimum ratio of applied electric field to gas pressure with respect to breakdown efficiency, this result may indicate that the optimum ratio was not achieved uniformly over the coil face, leading to non-uniform and incomplete current sheet formation in violation of the model assumption of immediate formation where all the injected propellant is contained in a magnetically-impermeable current sheet.

  12. Effect of Inductive Coil Geometry on the Operating Characteristics of a Pulsed Inductive Plasma Accelerator

    NASA Technical Reports Server (NTRS)

    Hallock, Ashley K.; Polzin, Kurt A.; Kimberlin, Adam C.

    2012-01-01

    Operational characteristics of two separate inductive thrusters with coils of different cone angles are explored through thrust stand measurements and time-integrated, un- filtered photography. Trends in impulse bit measurements indicate that, in the present experimental configuration, the thruster with the inductive coil possessing a smaller cone angle produced larger values of thrust, in apparent contradiction to results of a previous thruster acceleration model. Areas of greater light intensity in photographs of thruster operation are assumed to qualitatively represent locations of increased current density. Light intensity is generally greater in images of the thruster with the smaller cone angle when compared to those of the thruster with the larger half cone angle for the same operating conditions. The intensity generally decreases in both thrusters for decreasing mass ow rate and capacitor voltage. The location of brightest light intensity shifts upstream for decreasing mass ow rate of propellant and downstream for decreasing applied voltage. Recognizing that there typically exists an optimum ratio of applied electric field to gas pressure with respect to breakdown efficiency, this result may indicate that the optimum ratio was not achieved uniformly over the coil face, leading to non-uniform and incomplete current sheet formation in violation of the model assumption of immediate formation where all the injected propellant is contained in a magnetically-impermeable current sheet.

  13. Effects of coil location and injection flow rate in an inductively coupled RF plasma torch

    NASA Astrophysics Data System (ADS)

    Wei, D.; Apelian, D.; Farouk, B.

    1985-07-01

    A numerical model has been developed to investigate the effects of central carrier gas flow rate and coil location in an inductively coupled RF plasma torch. Solution algorithm is based on the primitive variable formulation of the Navier-Stokes equations and includes a pseudo two-dimensional electromagnetic field model. Computational results have shown that with increasing carrier gas flow rate, the plasma plume is penetrated and the back flow due to the magnetic pumping effects is diminished. This facilitates the delivery of powder particles into the discharge region. However, the plasma plume is also disturbed significantly thus enhancing power loss.

  14. Surface Modification of Nanometre Silicon Carbide Powder with Polystyrene by Inductively Coupled Plasma

    NASA Astrophysics Data System (ADS)

    Wei, Gang; Meng, Yuedong; Zhong, Shaofeng; Liu, Feng; Jiang, Zhongqing; Shu, Xingsheng; Ren, Zhaoxing; Wang, Xiangke

    2008-02-01

    An investigation was made into polystyrene (PS) grafted onto nanometre silicon carbide (SiC) particles. In our experiment, the grafting polymerization reaction was induced by a radio frequency (RF) inductively coupled plasma (ICP) treatment of the nanometre powder. FTIR (Fourier transform infrared spectrum) and XPS (X-ray photoelectron spectroscopy) results reveal that PS is grafted onto the surface of silicon carbide powder. An analysis is presented on the effectiveness of this approach as a function of plasma operating variables including the plasma treating power, treating time, and grafting reaction temperature and time.

  15. Temperature dependence of inductively coupled plasma assisted growth of TiN thin films.

    SciTech Connect

    Meng, W. J.; Curtis, T. J.; Rehn, L. E.; Baldo, P. M.; Materials Science Division; Louisiana State Univ.

    1999-11-01

    The use of low pressure high density plasmas to assist the synthesis of ceramic thin film materials is in its infancy. Using an inductively coupled plasma assisted magnetron sputtering system, we examine the dependence of plasma-assisted growth of TiN thin films on growth temperature at different ratios of ion flux to neutral atom flux. Our results indicate that a temperature independent densification of TiN films occurs above a certain ion to neutral atom flux ratio. As an example of this temperature independent densification, we demonstrate the formation of dense B1 TiN crystalline thin films at growth temperatures down to {approx}100 K.

  16. Evaluation of plasma pressure of high current low inductance vacuum spark on cathode surface

    NASA Astrophysics Data System (ADS)

    Sarantsev, S. A.

    2016-01-01

    This paper presents evaluation of the plasma pressure in a high current, low inductance vacuum spark on the cathode surface (the electrode material is steel). Calculations are provided for the first half period of the discharge, wherein the cathode surface is subjected to the most severe impacts (micropinches are created resulting in high-energy plasma beams). The evaluations were made using the experimental data obtained on the Pion device. The data of electrical measurements of the discharge current, the average plasma flow values obtained with the multi-grid probe and the data from a cathode macrostructure study were used. The results are given for different values of the discharge current.

  17. Development of very small-diameter, inductively coupled magnetized plasma device.

    PubMed

    Kuwahara, D; Mishio, A; Nakagawa, T; Shinohara, S

    2013-10-01

    In order to miniaturize a high-density, inductively coupled magnetized plasma or helicon plasma to be applied to, e.g., an industrial application and an electric propulsion field, small helicon device has been developed. The specifications of this device along with the experimental results are described. We have succeeded in generating high-density (~10(19) m(-3)) plasmas using quartz tubes with very small diameters of 10 and 20 mm, with a radio frequency power ~1200 and 700 W, respectively, in the presence of the magnetic field less than 1 kG. PMID:24182105

  18. Synthesis of Core-shell Structured Amorphous Si Nanoparticles by Induction Thermal Plasmas

    NASA Astrophysics Data System (ADS)

    Okamoto, Daisuke; Kageyama, Takuya; Tanaka, Manabu; Sone, Hirotaka; Watanabe, Takayuki

    2015-09-01

    Core-shell structured amorphous Si nanoparticles were synthesized by induction thermal plasma. Crystalline Si powder with 3 μm of average diameter was injected into the induction thermal plasma at 4 MHz. The Si raw materials immediately evaporate in the high temperature plasma region and nanoparticles were produced through the quenching process. Counterflow quenching gas was injected from downstream of the torch with its direction against the plasma flow. The effect of the operating parameter such as flow rate of quenching gas and input power was investigated. Collected particles were characterized by X-ray diffraction, transmission electron microscopy, electron energy-loss spectroscopy, and Raman spectroscopy. Obtained results indicate that amorphization degree of the synthesized nanoparticles is more than 90% when additional quenching gas of 20 L/min is injected. The quenching rate of the prepared nanoparticles in the growth region have an important role on determining the amorphization degree. Moreover, EELS and Raman analyses showed the synthesized nanoparticles were coated by the SiO2 shell with thickness of 2-4 nm. These findings indicated that amorphous Si/SiO2 core-shell structured nanoparticles were successfully synthesized by induction thermal plasma in single step.

  19. Relationship between the discharge mode and the spatial oxygen plasma distribution in a large size ferrite inductively coupled plasmas

    SciTech Connect

    Kim, Hyun Jun; Hwang, Hye Ju; Cho, Jeong Hee; Chae, Hee Sun; Kim, Dong Hwan; Chung, Chin-Wook

    2015-04-15

    The electrical characteristics and the spatial distribution of oxygen plasma according to the number of turns in ferrite inductively coupled plasmas (ferrite ICPs) are investigated. Through a new ICP model, which includes the capacitive coupling and the power loss of the ferrite material with the conventional ICP model, the variation of the oxygen discharge characteristics depending on the number of turns is simply understood by the electrical measurement, such as the antenna voltages and the currents. As the number of the turns increases, the capacitive coupling dominantly affects the spatial plasma distribution. This capacitive coupling results in a center focused density profile along the radial direction. In spite of the same discharge conditions (discharge chamber, neutral gas, and pressure), the spatial plasma distribution over 450 mm has drastic changes by increasing number of the turns. In addition, the effect of the negative species to the density profile is compared with the argon discharge characteristics at the same discharge configuration.

  20. On the possibility of the multiple inductively coupled plasma and helicon plasma sources for large-area processes

    SciTech Connect

    Lee, Jin-Won; Lee, Yun-Seong Chang, Hong-Young; An, Sang-Hyuk

    2014-08-15

    In this study, we attempted to determine the possibility of multiple inductively coupled plasma (ICP) and helicon plasma sources for large-area processes. Experiments were performed with the one and two coils to measure plasma and electrical parameters, and a circuit simulation was performed to measure the current at each coil in the 2-coil experiment. Based on the result, we could determine the possibility of multiple ICP sources due to a direct change of impedance due to current and saturation of impedance due to the skin-depth effect. However, a helicon plasma source is difficult to adapt to the multiple sources due to the consistent change of real impedance due to mode transition and the low uniformity of the B-field confinement. As a result, it is expected that ICP can be adapted to multiple sources for large-area processes.

  1. Effect of axial finiteness on electron heating in low-frequency inductively coupled plasmas

    SciTech Connect

    Aman-ur-Rehman; Pu, Y.-K.

    2006-10-15

    Total power absorption inside the plasma (by taking the thermal motion of the electrons into account) has been calculated using different inductively coupled plasma models. The comparison shows that in the low-frequency region the results of the semi-infinite plasma models are different from those of the finite-length plasma models. The semi-infinite plasma models show net reduction of heating in the low-frequency region, due to thermal motion of the electrons from inside the skin region to outside the skin region. The finite-length plasma models on the other hand (due to change in the skin depth owing to the boundary condition of E=0 at z=L, and reflection of electrons from the plasma boundary) show that the decrease in heating due to the motion of the electrons from inside the skin depth to outside the skin depth is recovered by the reflection of the electrons from the plasma boundary. Hence, it is concluded that the results of the semi-infinite plasma models presented by Tyshetskiy et al. [Phys Rev. Lett. 90, 255002 (2003)] can be misleading (in the low-frequency region), since they overlooked the effect of axial finiteness of the plasma.

  2. Evaluation of precursor evaporation in Si nanoparticle synthesis by inductively coupled thermal plasmas

    NASA Astrophysics Data System (ADS)

    Colombo, V.; Ghedini, E.; Gherardi, M.; Sanibondi, P.

    2013-06-01

    The evaporation of a micro-sized silicon solid precursor in a laboratory scale inductively coupled thermal plasma system for nanoparticle synthesis is investigated numerically using a customized version of the commercial CFD code ANSYS FLUENT©. Two turbulence models—the standard k-ɛ and the Reynolds stress model—and two different models for the computation of vapour production from the heated precursor—evaporation at boiling point and vaporization driven by vapour concentration gradients—are compared. The choice of the turbulence model can considerably influence the estimation of vapour production because plasma temperature reduction by plasma-particle heat exchange is increased when the flow in the torch region is predicted to be laminar, whereas the choice of the model for particle evaporation may be critical when the plasma temperature is decreased by plasma-particle heat exchange to values close to the boiling point of the material treated.

  3. Inductively-Coupled RF Powered O2 Plasma as a Sterilization Source

    NASA Technical Reports Server (NTRS)

    Sharma, S. P.; Rao, M. V. V. S.; Cruden, B. A.; Meyyappan, M.; Mogul, R.; Khare, B.; Chan, S. L.; Arnold, James O. (Technical Monitor)

    2001-01-01

    Low-temperature or cold plasmas have been shown to be effective for the sterilization of sensitive medical devices and electronic equipment. Low-temperature plasma sterilization procedures possess certain advantages over other protocols such as ethylene oxide, gamma radiation, and heat due to the use of inexpensive reagents, the insignificant environmental impacts and the low energy requirements. In addition, plasmas may also be more efficacious in the removal of robust microorganisms due to their higher chemical reactivity. Together, these attributes render cold plasma sterilization as ideal for the surface decontamination requirements for NASA Planetary Protection. Hence, the work described in this study involves the construction, characterization, and application of an inductively-coupled, RF powered oxygen (O2) plasma.

  4. Inductively Coupled Plasma-Induced Etch Damage of GaN p-n Junctions

    SciTech Connect

    SHUL,RANDY J.; ZHANG,LEI; BACA,ALBERT G.; WILLISON,CHRISTI LEE; HAN,JUNG; PEARTON,S.J.; REN,F.

    1999-11-03

    Plasma-induced etch damage can degrade the electrical and optical performance of III-V nitride electronic and photonic devices. We have investigated the etch-induced damage of an Inductively Coupled Plasma (ICP) etch system on the electrical performance of mesa-isolated GaN pn-junction diodes. GaN p-i-n mesa diodes were formed by Cl{sub 2}/BCl{sub 3}/Ar ICP etching under different plasma conditions. The reverse leakage current in the mesa diodes showed a strong relationship to chamber pressure, ion energy, and plasma flux. Plasma induced damage was minimized at moderate flux conditions ({le} 500 W), pressures {ge}2 mTorr, and at ion energies below approximately -275 V.

  5. Sample Preparation Problem Solving for Inductively Coupled Plasma-Mass Spectrometry with Liquid Introduction Systems I. Solubility, Chelation, and Memory Effects

    PubMed Central

    Pappas, R. Steven

    2015-01-01

    This tutorial was adapted from the first half of a course presented at the 7th International Conference on Sector Field Inductively Coupled Plasma Mass Spectrometry in 2008 and the 2012 Winter Conference on Plasma Spectrochemistry on sample preparation for liquid introduction systems. Liquid introduction in general and flow injection specifically are the most widely used sample introduction methods for inductively coupled plasma-mass spectrometry. Nevertheless, problems persist in determination of analytes that are commonly investigated, as well as in specialty applications for those seldom considered by most analysts. Understanding the chemistry that is common to different groups of analytes permits the development of successful approaches to rinse-out and elimination of memory effects. This understanding also equips the analyst for development of successful elemental analytical approaches in the face of a broad spectrum of matrices and other analytical challenges, whether the sample is solid or liquid. PMID:26321788

  6. Two-dimensional simulation of inductive-capacitive transition instability in an electronegative plasma

    NASA Astrophysics Data System (ADS)

    Kawamura, E.; Lieberman, M. A.; Lichtenberg, A. J.; Graves, D. B.

    2012-08-01

    Plasma instabilities are observed in low-pressure inductive discharges in the transition between low density capacitively driven and high density inductively driven discharges when attaching gases are used. A two-dimensional hybrid fluid-analytic simulation is used to determine the space- and time-varying densities of electrons, positive and negative ions, and neutral species, and electron and neutral gas temperatures. The simulation includes both the capacitive and inductive coupling of the source coils to the plasma and the neutral gas dissociation and heating. The plasma is described using the time-dependent fluid equations, along with an analytical sheath model. The simulation is applied to an experiment in Cl2, in which gaps in the electron and positive ion densities versus power curves were observed, with our numerical results indicating the existence of an inductive-capacitive transition instability, corresponding approximately to the observed gaps. The fluid calculation captures various features that are not included in previous global instability models. A method is developed to match the numerical results to the global model formalism, which predicts the existence of the unstable mode, as numerically found. The time and space variations can be used to improve the global model formalism.

  7. Collisionless electron heating in periodic arrays of inductively coupled plasmas

    SciTech Connect

    Czarnetzki, U.; Tarnev, Kh.

    2014-12-15

    A novel mechanism of collisionless heating in large planar arrays of small inductive coils operated at radio frequencies is presented. In contrast to the well-known case of non-local heating related to the transversal conductivity, when the electrons move perpendicular to the planar coil, we investigate the problem of electrons moving in a plane parallel to the coils. Two types of periodic structures are studied. Resonance velocities where heating is efficient are calculated analytically by solving the Vlasov equation. Certain scaling parameters are identified. The concept is further investigated by a single particle simulation based on the ergodic principle and combined with a Monte Carlo code allowing for collisions with Argon atoms. Resonances, energy exchange, and distribution functions are obtained. The analytical results are confirmed by the numerical simulation. Pressure and electric field dependences are studied. Stochastic heating is found to be most efficient when the electron mean free path exceeds the size of a single coil cell. Then the mean energy increases approximately exponentially with the electric field amplitude.

  8. Lithium Iron Phosphate Powders and Coatings Obtained by Means of Inductively Coupled Thermal Plasma

    NASA Astrophysics Data System (ADS)

    Major, K.; Veilleux, J.; Brisard, G.

    2016-01-01

    Lithium-ion batteries have high energy efficiency and good cycling life and are considered as one of the best energy storage device for hybrid and/or electrical vehicle. Still, several problems must be solved prior to a broad adoption by the automotive industry: energy density, safety, and costs. To enhance both energy density and safety, the current study aims at depositing binder-free cathode materials using inductively coupled thermal plasma. In a first step, lithium iron phosphate (LiFePO4) powders are synthesized in an inductively coupled thermal plasma reactor and dispersed in a conventional polyvinylidene fluoride (PVDF) binder. Then, binder-free LiFePO4 coatings are directly deposited onto nickel current collectors by solution precursor plasma spraying (SPPS). The morphology, microstructure, and composition of the synthesized LiFePO4 powders and coatings are fully characterized by electronic microscopy, x-ray diffraction, and x-ray photoelectron spectroscopy (XPS). Quantifying Li with XPS requires the substitution of iron with manganese in the SPPS precursors (LiMPO4, where M = Fe or Mn). The plasma-derived cathodes (with and without PVDF binder) are assembled in button cells and tested. Under optimized plasma conditions, cyclic voltammetry shows that the electrochemical reversibility of plasma-derived cathodes is improved over that of conventional sol-gel-derived LiFePO4 cathodes.

  9. ''SensArray'' voltage sensor analysis in an inductively coupled plasma

    SciTech Connect

    Titus, M. J.; Hsu, C. C.; Graves, D. B.

    2010-01-15

    A commercially manufactured PlasmaVolt sensor wafer was studied in an inductively coupled plasma reactor in an effort to validate sensor measurements. A pure Ar plasma at various powers (25-420 W), for a range of pressures (10-80 mT), and bias voltages (0-250 V) was utilized. A numerical sheath simulation was simultaneously developed in order to interpret experimental results. It was found that PlasmaVolt sensor measurements are proportional to the rf-current through the sheath. Under conditions such that the sheath impedance is dominantly capacitive, sensor measurements follow a scaling law derived from the inhomogeneous sheath model of Lieberman and Lichtenberg, [Principles of Plasma Discharges and Materials Processing (Wiley, New York, 2005)]. Under these conditions, sensor measurements are proportional to the square root of the plasma density at the plasma-sheath interface, the one-fourth root of the electron temperature, and the one-fourth root of the rf bias voltage. When the sheath impedance becomes increasingly resistive, the sensor measurements deviate from the scaling law and tend to be directly proportional to the plasma density. The measurements and numerical sheath simulation demonstrate the scaling behavior as a function of changing sheath impedance for various plasma conditions.

  10. 15th International Congress on Plasma Physics & 13th Latin American Workshop on Plasma Physics

    NASA Astrophysics Data System (ADS)

    Soto, Leopoldo

    2014-05-01

    The International Advisory Committee of the 15th International Congress on Plasma Physics (ICPP 2010) and the International Advisory Committee of the 13th Latin American Workshop on Plasma Physics (LAWPP 2010), together agreed to carry out this combined meeting ICPP-LAWPP-2010 in Santiago de Chile, 8-13 August 2010, on occasion of the Bicentennial of Chilean Independence. The ICPP-LAWPP-2010 was organized by the Thermonuclear Plasma Department of the Chilean Nuclear Energy Commission (CCHEN) as part of the official program within the framework of the Chilean Bicentennial. The event was also a scientific and academic activity of the project ''Center for Research and Applications in Plasma Physics and Pulsed Power, P4'', supported by National Scientific and Technological Commission, CONICYT-Chile, under grant ACT-26. The International Congress on Plasma Physics was first held in Nagoya, in 1980, and followed by the Congresses: Gothenburg (1982), Lausanne (1984), Kiev (1987), New Delhi (1989), Innsbruck (1992), Foz do Iguacu (1994), Nagoya (1996), Prague (1998), Quebec City (2000), Sydney (2002), Nice (2004), Kiev (2006), and Fukuoka (2008). The purpose of the Congress is to discuss the recent progress and future views in plasma science, including fundamental plasma physics, fusion plasmas, astrophysical plasmas, and plasma applications, and so forth. The Latin American Workshop on Plasma Physics was first held in 1982 in Cambuquira, Brazil, followed by the Workshops: Medellín (1985), Santiago (1988), Buenos Aires (1990), Mexico City (1992), Foz do Iguacu (1994, also combined with ICPP), Caracas (1997), Tandil (1998), La Serena (2000), Sao Pedro (2003), Mexico City (2005), and Caracas (2007). The Latin American Workshop on Plasma Physics is a communication forum of the achievements of the plasma-physics regional community, fostering collaboration between plasma scientists within the region and elsewhere. The program of the ICPP-LAWPP-2010 included the topics

  11. Development and characterization of induction heating electrothermal vaporization (IH-ETV) sample introduction for inductively coupled plasma spectrometry

    NASA Astrophysics Data System (ADS)

    Rybak, Michael E.; Salin, Eric D.

    2001-03-01

    A general study of performance attributes was conducted for a prototypical electrothermal vaporization (ETV) sample introduction system, in which induction heating (IH) was used to facilitate the drying, pyrolysis, and vaporization of samples from long, undercut graphite cup probes in a radio-frequency (RF) induction field. In the first part of this study, experiments were carried out to determine the heating characteristics and temperature control aspects of an IH-ETV arrangement. Using a remote-sensing infrared thermocouple, it was determined that a 3/8-inch (9.53-mm) outer diameter graphite cup sample probe could be heated to a maximum temperature of 1860°C in the induction field of the IH-ETV under full forward power (1.5 kW). The IH-ETV device was found to have a rapid heating response (1/ e time-constant of 2.0±0.2 s) that was independent of the initial/final temperatures chosen. Linear temperature control was possible by regulating either the DC voltage applied to the plate or the current flowing to the grid of the RF generator oscillator tube. The second part of this work consisted of studies to establish benchmarks, such as limits of detection (LOD) with inductively coupled plasma optical emission spectrometry (ICP-OES) and transport efficiency for analyte vaporization under several x-Ar mixed gas atmospheres [where x=15% N 2, 10% O 2, HCl (sparged), or 15% SF 6 (v/v)]. In general, reproducible transient signals with evolution times of 5-15 s were seen for the vaporization of most elements studied, with peak area intensity and reproducibility generally being the best with SF 6-Ar. A 10-fold increase in transport efficiency was seen for refractory carbide-forming analytes (Cr, V) when vaporization was conducted in a halogenous ( x=HCl, SF 6) versus non-halogenous ( x=N 2, O 2) environment, with a two-fold improvement being observed for most other non-refractory elements (Cd, Cu, Fe, Mn, Ni, Pb, Zn). The transport of arsenic proved to be a special case

  12. Ignition delay of a pulsed inductively coupled plasma (ICP) in tandem with an auxiliary ICP

    NASA Astrophysics Data System (ADS)

    Liu, Lei; Sridhar, Shyam; Donnelly, Vincent M.; Economou, Demetre J.

    2015-12-01

    Plasma ignition delays were observed in a ‘main’ inductively coupled plasma (ICP), in tandem with an ‘auxiliary’ ICP. The Faraday-shielded ICPs were separated by a grounded metal grid. Power (13.56 MHz) to the main ICP was pulsed with a frequency of 1 kHz, while the auxiliary ICP was operated in continuous wave (cw) mode. In chlorine plasmas, ignition delay was observed for duty cycles greater than 60% and, in contrast to expectation, the delay was longer with increasing duty cycle up to ~99.5%. The ignition delay could be varied by changing the auxiliary and/or main ICP power. Langmuir probe measurements provided the temporal evolution of electron temperature, and electron and positive ion densities. These measurements revealed that the plasma was ignited shortly after the decaying positive ion density (n +), in the afterglow of the main ICP, reached the density ({{n}+},\\text{aux} ) prevailing when only the auxiliary ICP was powered. At that time, production of electrons began to dominate their loss in the main ICP, due to hot electron injection from the auxiliary ICP. As a result, {{n}\\text{e}} increased from a value below {{n}\\text{e,\\text{aux}}} , improving inductive power coupling efficiency, further increasing plasma density leading to plasma ignition. Plasma ignition delay occurred when the afterglow of the pulsed plasma was not long enough for the ion density to reach {{n}+},\\text{aux} during the afterglow. Besides Cl2, plasma ignition delays were also observed in other electronegative gases (SF6, CF4/O2 and O2) but not in an electropositive gas (Ar).

  13. Cocaine induction of dopamine transporter trafficking to the plasma membrane.

    PubMed

    Little, Karley Y; Elmer, Lawrence W; Zhong, Huailing; Scheys, Joshua O; Zhang, Lian

    2002-02-01

    Several previous human postmortem experiments have detected an increase in striatal [(3)H]WIN 35428 binding to the dopamine transporter (DAT) in chronic cocaine users. However, animal experiments have found considerable variability in DAT radioligand binding levels in brain after cocaine administration, perhaps caused by length and dose of treatment and type of radioligand used. The present experiments tested the hypothesis that [(3)H]WIN 35428 binding and [(3)H]dopamine uptake would be increased by exposure to cocaine through alterations in DAT cellular trafficking, rather than increased protein synthesis. Experiments were conducted in stably hDAT-transfected N2A cells and assessed the dose response and time course of cocaine effects on [(3)H]WIN 35428 binding to the DAT, [(3)H]dopamine uptake, measures of DAT protein and mRNA, as well as DAT subcellular location. Cocaine doses of 10(-6) M caused statistically significant increases in [(3)H]WIN 35428 binding and [(3)H]dopamine uptake after 12 and 3 h, respectively. Despite these increases in DAT function, there was no change in DAT total protein or mRNA. Immunofluorescence and biotinylation experiments indicated that cocaine treatment induced increases in plasma membrane DAT immunoreactivity and intracellular decreases. The present model system may further our understanding of regulatory alterations in DAT radioligand binding and function caused by cocaine exposure. PMID:11809869

  14. PREFACE: Third International Workshop & Summer School on Plasma Physics 2008

    NASA Astrophysics Data System (ADS)

    Benova, E.; Dias, F. M.; Lebedev, Yu

    2010-01-01

    The Third International Workshop & Summer School on Plasma Physics (IWSSPP'08) organized by St Kliment Ohridsky University of Sofia, with co-organizers TCPA Foundation, Association EURATOM/IRNRE, The Union of the Physicists in Bulgaria, and the Bulgarian Academy of Sciences was held in Kiten, Bulgaria, at the Black Sea Coast, from 30 June to 5 July 2008. A Special Session on Plasmas for Environmental Issues was co-organised by the Institute of Plasmas and Nuclear Fusion, Lisbon, Portugal and the Laboratory of Plasmas and Energy Conversion, University of Toulouse, France. That puts the beginning of a series in Workshops on Plasmas for Environmental Issues, now as a satellite meeting of the European Physical Society Conference on Plasma Physics. As the previous issues of this scientific meeting (IWSSPP'05, J. Phys.: Conf. Series 44 (2006) and IWSSPP'06, J. Phys.: Conf. Series 63 (2007)), its aim was to stimulate the creation and support of a new generation of young scientists for further development of plasma physics fundamentals and applications, as well as to ensure an interdisciplinary exchange of views and initiate possible collaborations by bringing together scientists from various branches of plasma physics. This volume of Journal of Physics: Conference Series includes 38 papers (invited lectures, contributed talks and posters) devoted to various branches of plasma physics, among them fusion plasma and materials, dc and microwave discharge modelling, transport phenomena in gas discharge plasmas, plasma diagnostics, cross sections and rate constants of elementary processes, material processing, plasma-chemistry and technology. Some of them have been presented by internationally known and recognized specialists in their fields; others are MSc or PhD students' first steps in science. In both cases, we believe they will raise readers' interest. We would like to thank the members of both the International Advisory Committee and the Local Organizing Committee, the

  15. Investigation of large-area multicoil inductively coupled plasma sources using three-dimensional fluid model

    NASA Astrophysics Data System (ADS)

    Brcka, Jozef

    2016-07-01

    A multi inductively coupled plasma (ICP) system can be used to maintain the plasma uniformity and increase the area processed by a high-density plasma. This article presents a source in two different configurations. The distributed planar multi ICP (DM-ICP) source comprises individual ICP sources that are not overlapped and produce plasma independently. Mutual coupling of the ICPs may affect the distribution of the produced plasma. The integrated multicoil ICP (IMC-ICP) source consists of four low-inductance ICP antennas that are superimposed in an azimuthal manner. The identical geometry of the ICP coils was assumed in this work. Both configurations have highly asymmetric components. A three-dimensional (3D) plasma model of the multicoil ICP configurations with asymmetric features is used to investigate the plasma characteristics in a large chamber and the operation of the sources in inert and reactive gases. The feasibility of the computational calculation, the speed, and the computational resources of the coupled multiphysics solver are investigated in the framework of a large realistic geometry and complex reaction processes. It was determined that additional variables can be used to control large-area plasmas. Both configurations can form a plasma, that azimuthally moves in a controlled manner, the so-called “sweeping mode” (SM) or “polyphase mode” (PPM), and thus they have the potential for large-area and high-density plasma applications. The operation in the azimuthal mode has the potential to adjust the plasma distribution, the reaction chemistry, and increase or modulate the production of the radicals. The intrinsic asymmetry of the individual coils and their combined operation were investigated within a source assembly primarily in argon and CO gases. Limited investigations were also performed on operation in CH4 gas. The plasma parameters and the resulting chemistry are affected by the geometrical relation between individual antennas. The aim of

  16. PREFACE: Second International Workshop & Summer School on Plasma Physics 2006

    NASA Astrophysics Data System (ADS)

    Benova, Evgeniya; Atanassov, Vladimir

    2007-04-01

    The Second International Workshop & Summer School on Plasma Physics (IWSSPP'06) organized by St. Kliment Ohridsky University of Sofia, The Union of the Physicists in Bulgaria, the Bulgarian Academy of Sciences and the Bulgarian Nuclear Society, was held in Kiten, Bulgaria, on the Black Sea Coast, from 3-9 July 2006. As with the first of these scientific meetings (IWSSPP'05 Journal of Physics: Conference Series 44 (2006)), its aim was to stimulate the creation and support of a new generation of young scientists for further development of plasma physics fundamentals and applications, as well as to ensure an interdisciplinary exchange of views and initiate possible collaborations by bringing together scientists from various branches of plasma physics. This volume of Journal of Physics: Conference Series includes 33 papers (invited lectures, contributed talks and posters) devoted to various branches of plasma physics, among them fusion plasma research, dc and microwave discharge modelling, transport phenomena in gas discharge plasmas, plasma diagnostics, cross sections and rate constants of elementary processes, material processing, plasma-chemistry and technology. Some of these papers were presented by internationally known and recognized specialists in their fields; others are MSc or PhD students' first steps in science. In both cases, we believe they will raise readers' interest. We would like to thank the members of both the International Advisory Committee and the Local Organizing Committee, the participants who sent their manuscripts and passed through the (sometimes heavy and troublesome) refereeing and editing procedure and our referees for their patience and considerable effort to improve the manuscripts. We greatly appreciate the financial support from the sponsors: the Department for Language Teaching and International Students at the University of Sofia and Natsionalna Elektricheska Kompania EAD. We would like to express our gratitude to the invited

  17. Electron density measurement of inductively coupled plasmas by terahertz time-domain spectroscopy (THz-TDS)

    SciTech Connect

    Ando, Ayumi; Kurose, Tomoko; Kitano, Katsuhisa; Hamaguchi, Satoshi; Reymond, Vivien; Kitahara, Hideaki; Takano, Keisuke; Hangyo, Masanori; Tani, Masahiko

    2011-10-01

    The electron densities of argon inductively coupled plasmas were measured by terahertz time-domain spectroscopy (THz-TDS). At a low pressure, the electron densities were also measured with a Langmuir-type double probe and the validity of THz-TDS electron-density measurement in a plasma has been corroborated. As the input radio-frequency (RF) power increases, the plasma density and gas temperature increase, which makes the probe measurement less reliable or even impossible, due to the large heat load to the probe surface. On the contrary, the THz-TDS measurement is unaffected by the gas temperature and becomes more reliable due to the higher electron density at higher input power for plasma generation.

  18. New Applications of Inductively Coupled Plasma-Mass Spectrometry in the Nuclear Industry

    SciTech Connect

    Rob Henry; Dagmar Koller; Phil Marriott

    1998-12-31

    Inductively coupled plasma mass spectrometry (ICP-MS) complements the traditional methods of quantitation of radioactive isotopes. Because of the favorable ionization potential of most actinides and their daughter products, the argon plasma provides a rich, stable source of ions, which are introduced through a plasma-mass spectrometer interface into the mass spectrometer for isotopic separation. Samples are normally introduced in solution, although direct solids analysis has also been achieved using laser ablation of the sample into the argon plasma. Since 1983, improvements in ICP-MS sensitivity have resulted in correspondingly lower mass detection capability. This development has in turn expanded the number of isotopes accessible to measurement at the levels required in the nuclear industry.

  19. Langmuir Probe Measurements in an Inductively Coupled GEC Reference Cell Plasma

    NASA Technical Reports Server (NTRS)

    Ji, J. S.; Kim, J. S.; Cappelli, M. A.; Sharma, S. P.; Arnold, J. O. (Technical Monitor)

    1998-01-01

    Measurements of electron number density, electron temperature, and electron energy distribution function (EEDF) using a compensated Langmuir probe have been performed on an inductively (transformer ) coupled Gaseous Electronics Conference (GEC) reference cell plasma. The plasma source is operated with CH4, CF4, or their mixtures with argon. The effect of independently driving the electrode supporting the wafer on the probe data is studied. In particular, we find that the plasma structure depends on the phase in addition to the magnitude of the power coupled to the electrode relative to that of the transformer coil. The Langmuir probe is translated in a plane parallel to the electrode to investigate the spatial structure of the plasma. The probe data is also compared with fluid model predictions.

  20. Current-free double-layer formation in inductively coupled plasma in a uniform magnetic field

    SciTech Connect

    Popescu, S.; Ohtsu, Y.; Fujita, H.

    2006-06-15

    The axial profiles of plasma parameters for low and moderate pressures, such as the plasma potential, electron temperature, and number density, have been evaluated in magnetized inductively coupled plasma. The experimental results revealed in both cases the existence of a genuine current-free double-layer structure, separating two plasma regions with different properties. Based on the experimental results, a physical scenario for the self-assembling of the double layer is proposed. Also, the axial profile of the electron number density downstream is analyzed, emphasizing the role of neutral metastable ionization, and a simple analytical model is developed to fit the experimental data. The model allows the estimation of neutral metastable number density downstream and the recombination rate coefficient.

  1. Langmuir Probe Measurements in an Inductively Coupled Ar/CF4 Plasmas

    NASA Technical Reports Server (NTRS)

    Rao, M. V. V. S.; Meyyappan, M.; Sharma, S. P.; Arnold, James O. (Technical Monitor)

    2000-01-01

    Technological advancement in the microelectronics industry requires an understanding of the physical and chemical processes occurring in plasmas of fluorocarbon gases, such as carbon tetrafluoride (CF4) which is commonly used as an etchant, and their mixtures to optimize various operating parameters. In this paper we report data on electron number density (ne), electron temperature'(Te), electron energy distribution function (EEDF), mean electron energy, ion number density (ni), and plasma potential (Vp) measured by using Langmuir probe in an inductively coupled 13.56 MHz radio frequency plasmas generated in 50%Ar:50%CF4 mixture in the GEC cell. The probe data were recorded at various radial positions providing radial profiles of these plasma parameters at 10-50 mTorr pressures and 200 W and 300 W of RF power. Present measurements indicate that the electron and ion number densities increase with increase in pressure and power. Whereas the plasma potential and electron temperature decrease with increase in pressure, and they weakly depend on RF power. The radial profiles exhibit that the electron and ion number densities and the plasma potential peak at the center of the plasma with an exponential fall away from it, while the electron temperature has a minimum at the center and it increases steadily towards the electrode edge. The EEDFs have a characteristic drop near the low energy end at all pressures and pressures and their shapes represent non-Maxwellian plasma and exhibit more like Druyvesteyn energy distribution.v

  2. Induction-linac based free-electron laser amplifiers for plasma heating

    SciTech Connect

    Jong, R.A.

    1988-08-22

    We describe an induction-linac based free-electron laser amplifier that is presently under construction at the Lawrence Livermore National Laboratory. It is designed to produce up to 2 MW of average power at a frequency of 250 GHz for plasma heating experiments in the Microwave Tokamak Experiment. In addition, we shall describe a FEL amplifier design for plasma heating of advanced tokamak fusion devices. This system is designed to produce average power levels of about 10 MW at frequencies ranging form 280 to 560 GHz. 7 refs., 1 tab.

  3. Inductive Pulsed Plasma Thruster Model with Time-Evolution of Energy and State Properties

    NASA Technical Reports Server (NTRS)

    Polzin, Kurt A.; Sankaran, Kamesh

    2012-01-01

    A model for pulsed inductive plasma acceleration is presented that consists of a set of circuit equations coupled to both a one-dimensional equation of motion and an equation governing the partitioning of energy. The latter two equations are obtained for the plasma current sheet by treating it as a single element of finite volume and integrating the governing equations over that volume. The integrated terms are replaced where necessary by physically-equivalent quantities that are calculated through the solution of other parts of the governing equation set. The model improves upon previous one-dimensional performance models by permitting the time-evolution of the energy and state properties of the plasma, the latter allowing for the tailoring of the model to different gases that may be chosen as propellants. The time evolution of the various energy modes in the system and the associated plasma properties, calculated for argon propellant, are presented to demonstrate the efficacy of the model. The model produces a result where efficiency is maximized at a given value of the electrodynamic scaling term known as the dynamic impedance parameter. Qualitatively and quantitatively, the model compares favorably with performance measured for two separate inductive pulsed plasma thrusters, with disagreements attributable to simplifying assumptions employed in the generation of the model solution.

  4. Numerical and Experimental Investigation on the Attenuation of Electromagnetic Waves in Unmagnetized Plasmas Using Inductively Coupled Plasma Actuator

    NASA Astrophysics Data System (ADS)

    Lin, Min; Xu, Haojun; Wei, Xiaolong; Liang, Hua; Song, Huimin; Sun, Quan; Zhang, Yanhua

    2015-10-01

    The attenuation of electromagnetic (EM) waves in unmagnetized plasma generated by an inductively coupled plasma (ICP) actuator has been investigated both theoretically and experimentally. A numerical study is conducted to investigate the propagation of EM waves in multilayer plasma structures which cover a square flat plate. Experimentally, an ICP actuator with dimensions of 20 cm×20 cm×4 cm is designed to produce a steady plasma slab. The attenuation of EM waves in the plasma generated by the ICP actuator is measured by a reflectivity arch test method at incident waves of 2.3 GHz and 10.1 GHz, respectively. A contrastive analysis of calculated and measured results of these incident wave frequencies is presented, which suggests that the experiment accords well with our theory. As expected, the plasma slab generated by the ICP actuator can effectively attenuate the EM waves, which may have great potential application prospects in aircraft stealth. supported by National Natural Science Foundation of China (Nos. 51276197, 11472306 and 11402301)

  5. Boron determination in steels by Inductively-Coupled Plasma spectometry (ICP)

    NASA Technical Reports Server (NTRS)

    Coedo, A. G.; Lopez, M. T. D.

    1986-01-01

    The sample is treated with 5N H2SO4 followed by concentrated HNO3 and the diluted mixture is filtered. Soluble B is determined in the filtrate by Inductively-Coupled Plasma (ICP) spectrometry after addition HCl and extraction of Fe with ethyl-ether. The residue is fused with Na2CO3 and, after treatment with HCl, the insoluble B is determined by ICP spectrometry as before. The method permits determination of ppm amounts of B in steel.

  6. Iron-Isotopic Fractionation Studies Using Multiple Collector Inductively Coupled Plasma Mass Spectrometry

    NASA Technical Reports Server (NTRS)

    Anbar, A. D.; Zhang, C.; Barling, J.; Roe, J. E.; Nealson, K. H.

    1999-01-01

    The importance of Fe biogeochemistry has stimulated interest in Fe isotope fractionation. Recent studies using thermal ionization mass spectrometry (TIMS) and a "double spike" demonstrate the existence of biogenic Fe isotope effects. Here, we assess the utility of multiple-collector inductively-coupled plasma mass spectrometry(MC-ICP-MS) with a desolvating sample introduction system for Fe isotope studies, and present data on Fe biominerals produced by a thermophilic bacterium. Additional information is contained in the original extended abstract.

  7. In situ calibration of inductively coupled plasma-atomic emission and mass spectroscopy

    DOEpatents

    Braymen, S.D.

    1996-06-11

    A method and apparatus are disclosed for in situ addition calibration of an inductively coupled plasma atomic emission spectrometer or mass spectrometer using a precision gas metering valve to introduce a volatile calibration gas of an element of interest directly into an aerosol particle stream. The present in situ calibration technique is suitable for various remote, on-site sampling systems such as laser ablation or nebulization. 5 figs.

  8. Performance scaling of inductive pulsed plasma thrusters with coil angle and pulse rate

    NASA Astrophysics Data System (ADS)

    Martin, A. K.

    2016-01-01

    A circuit model for an inductive pulsed plasma thruster was developed in order to investigate the performance of thrusters with conical coils; the model can accommodate cone-angles from 0° (a straight theta-pinch coil) to 90° (a planar coil). The plasma is treated as a deformable slug that moves both radially and axially in response to the force applied by the coil. The radial equation of motion includes a restoring force due to the plasma pressure, which is derived under the assumption that the electron population is isothermal, while the ions are isothermal, adiabatic, or shock-heated depending on the magnitude and sign of the radial velocity. The inductance of the coil and the plasma slug, and their mutual inductance, was determined using QuickField. A local maximum in efficiency and specific impulse was found for angles less than 90° however the absolute maximum for both these quantities occurs at 90°. High pulse-rate operation was found to yield dynamic efficiencies (excluding ionization cost) as high as 60-70% for I SP in the range of 3000-5000 s, even for a device with modest jet-power (5 kW). This mode of operation also permits elimination of the pulsed gas valve, which would be a significant system-level simplification. An alternate mode of inductive recapture, in which the current is interrupted at the second zero-crossing, was found to result in a sacrifice of only 1-2% in efficiency, while offering other significant system-level benefits for this kind of thruster.

  9. Determination of minor elements in steelmaking flue dusts using laser ablation inductively coupled plasma mass spectrometry.

    PubMed

    Coedo, A G; Padilla, I; Dorado, M T

    2005-07-15

    Element determination in solid waste products from the steel industry usually involves the time-consuming step of preparing a solution of the solid. Laser ablation (LA) inductively coupled plasma mass spectrometry (ICP-MS) has been applied to the analysis of Cr, Ni, Cu, As, Cd and Sn, elements of importance from the point of view of their impact on the environment, in electric arc furnace flue dust (EAFD). A simple method of sample preparation as pressed pellets using a mixture of cellulose and paraffin as binder material was applied. Calibration standards were prepared spiking multielement solution standards to a 1:1 ZnO+Fe(2)O(3) synthetic matrix. The wet powder was dried and mechanically homogenised. Quantitative analysis were based on external calibration using a set of matrix matched calibration standards with Rh as a internal standard. Results obtained using only one-point for calibration without matrix matched, needing less time for standardization and data processing, are also presented. Data are calculated for flue dust reference materials: CRM 876-1 (EAFD), AG-6203 (EAFD), AG-6201 (cupola dust) and AG-SX3705 (coke ashes), and for two representative electrical arc furnace flue dusts samples from Spanish steelmaking companies: MS-1 and MS-2. For the reference materials, an acceptable agreement with certificate values was achieved, and the results for the MS samples matched with those obtained from conventional nebulization solutions (CN). The analytical precision was found to be better than 7% R.S.D. both within a single pellet and between several pellets of the same sample for all the elements. PMID:18970147

  10. PREFACE: First International Workshop and Summer School on Plasma Physics

    NASA Astrophysics Data System (ADS)

    Benova, Evgenia; Zhelyazkov, Ivan; Atanassov, Vladimir

    2006-07-01

    The First International Workshop and Summer School on Plasma Physics (IWSSPP'05) organized by The Faculty of Physics, University of Sofia and the Foundation `Theoretical and Computational Physics and Astrophysics' was dedicated to the World Year of Physics 2005 and held in Kiten, Bulgaria, on the Black Sea Coast, from 8--12 June 2005. The aim of the workshop was to bring together scientists from various branches of plasma physics in order to ensure an interdisciplinary exchange of views and initiate possible collaborations. Another important task was to stimulate the creation and support of a new generation of young scientists for the further development of plasma physics fundamentals and applications. This volume of Journal of Physics: Conference Series includes 31 papers (invited lectures, contributed talks and posters) devoted to various branches of plasma physics, among them fusion research, kinetics and transport phenomena in gas discharge plasmas, MHD waves and instabilities in the solar atmosphere, dc and microwave discharge modelling, plasma diagnostics, cross sections and rate constants of elementary processes, material processing, plasma-chemistry and technology. Some of them have been presented by internationally known and recognized specialists in their fields; others are Masters or PhD students' first steps in science. In both cases, we believe they will stimulate readers' interest. We would like to thank the members of both the International Advisory Committee and the Local Organizing Committee. We greatly appreciate the financial support from the sponsors: the Department for Language Teaching and International Students at Sofia University, Dr Ivan Bogorov Publishing house, and Artgraph2 Publishing house. We would like to express our gratitude to the invited lecturers who were willing to pay the participation fee. In this way, in addition to the intellectual support they provided by means of their excellent lectures, they also supported the school

  11. Two-Dimensional Analysis of Conical Pulsed Inductive Plasma Thruster Performance

    NASA Technical Reports Server (NTRS)

    Hallock, A. K.; Polzin, K. A.; Emsellem, G. D.

    2011-01-01

    A model of the maximum achievable exhaust velocity of a conical theta pinch pulsed inductive thruster is presented. A semi-empirical formula relating coil inductance to both axial and radial current sheet location is developed and incorporated into a circuit model coupled to a momentum equation to evaluate the effect of coil geometry on the axial directed kinetic energy of the exhaust. Inductance measurements as a function of the axial and radial displacement of simulated current sheets from four coils of different geometries are t to a two-dimensional expression to allow the calculation of the Lorentz force at any relevant averaged current sheet location. This relation for two-dimensional inductance, along with an estimate of the maximum possible change in gas-dynamic pressure as the current sheet accelerates into downstream propellant, enables the expansion of a one-dimensional circuit model to two dimensions. The results of this two-dimensional model indicate that radial current sheet motion acts to rapidly decouple the current sheet from the driving coil, leading to losses in axial kinetic energy 10-50 times larger than estimations of the maximum available energy in the compressed propellant. The decreased available energy in the compressed propellant as compared to that of other inductive plasma propulsion concepts suggests that a recovery in the directed axial kinetic energy of the exhaust is unlikely, and that radial compression of the current sheet leads to a loss in exhaust velocity for the operating conditions considered here.

  12. Inductively coupled plasma mass spectrometry for stable isotope metabolic tracer studies of living systems

    SciTech Connect

    Luong, E.

    1999-05-10

    This dissertation focuses on the development of methods for stable isotope metabolic tracer studies in living systems using inductively coupled plasma single and dual quadrupole mass spectrometers. Sub-nanogram per gram levels of molybdenum (Mo) from human blood plasma are isolated by the use of anion exchange alumina microcolumns. Million-fold more concentrated spectral and matrix interferences such as sodium, chloride, sulfate, phosphate, etc. in the blood constituents are removed from the analyte. The recovery of Mo from the alumina column is 82 {+-} 5% (n = 5). Isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS) is utilized for the quantitative ultra-trace concentration determination of Mo in bovine and human blood samples. The average Mo concentration in reference bovine serum determined by this method is 10.2 {+-} 0.4 ng/g, while the certified value is 11.5 {+-} 1.1 ng/g (95% confidence interval). The Mo concentration of one pool of human blood plasma from two healthy male donors is 0.5 {+-} 0.1 ng/g. The inductively coupled plasma twin quadrupole mass spectrometer (ICP-TQMS) is used to measure the carbon isotope ratio from non-volatile organic compounds and bio-organic molecules to assess the ability as an alternative analytical method to gas chromatography combustion isotope ratio mass spectrometry (GC-combustion-IRMS). Trytophan, myoglobin, and {beta}-cyclodextrin are chosen for the study, initial observation of spectral interference of {sup 13}C{sup +} with {sup 12}C{sup 1}H{sup +} comes from the incomplete dissociation of myoglobin and/or {beta}-cyclodextrin.

  13. EVALUATION OF A MULTICHANNEL INDUCTIVELY COUPLED PLASMA-OPTICAL EMISSION SPECTROMETER MODIFIED TO MINIMIZE AND CORRECT SCATTERED LIGHT EFFECTS

    EPA Science Inventory

    In a study of an inductively coupled plasma optical emission spectrometer, data from an early commercially available instrument are compared with data from the same instrument after modifications to correct observed inadequacies were made. Results show negligible changes in power...

  14. On-line elemental analysis of fossil fuel process streams by inductively coupled plasma spectrometry

    SciTech Connect

    Chisholm, W.P.

    1995-06-01

    METC is continuing development of a real-time, multi-element plasma based spectrometer system for application to high temperature and high pressure fossil fuel process streams. Two versions are under consideration for development. One is an Inductively Coupled Plasma system that has been described previously, and the other is a high power microwave system. The ICP torch operates on a mixture of argon and helium with a conventional annular swirl flow plasma gas, no auxiliary gas, and a conventional sample stream injection through the base of the plasma plume. A new, demountable torch design comprising three ceramic sections allows bolts passing the length of the torch to compress a double O-ring seal. This improves the reliability of the torch. The microwave system will use the same data acquisition and reduction components as the ICP system; only the plasma source itself is different. It will operate with a 750-Watt, 2.45 gigahertz microwave generator. The plasma discharge will be contained within a narrow quartz tube one quarter wavelength from a shorted waveguide termination. The plasma source will be observed via fiber optics and a battery of computer controlled monochromators. To extract more information from the raw spectral data, a neural net computer program is being developed. This program will calculate analyte concentrations from data that includes analyte and interferant spectral emission intensity. Matrix effects and spectral overlaps can be treated more effectively by this method than by conventional spectral analysis.

  15. Induction of plasma acetylcholinesterase activity in mice challenged with organophosphorus poisons

    SciTech Connect

    Duysen, Ellen G.; Lockridge, Oksana

    2011-09-01

    The restoration of plasma acetylcholinesterase activity in mice following inhibition by organophosphorus pesticides and nerve agents has been attributed to synthesis of new enzyme. It is generally assumed that activity levels return to normal, are stable and do not exceed the normal level. We have observed over the past 10 years that recovery of acetylcholinesterase activity levels in mice treated with organophosphorus agents (OP) exceeds pretreatment levels and remains elevated for up to 2 months. The most dramatic case was in mice treated with tri-cresyl phosphate and tri-ortho-cresyl phosphate, where plasma acetylcholinesterase activity rebounded to a level 250% higher than the pretreatment activity. The present report summarizes our observations on plasma acetylcholinesterase activity in mice treated with chlorpyrifos, chlorpyrifos oxon, diazinon, tri-ortho-cresyl phosphate, tri-cresyl phosphate, tabun thiocholine, parathion, dichlorvos, and diisopropylfluorophosphate. We have developed a hypothesis to explain the excess acetylcholinesterase activity, based on published observations. We hypothesize that acetylcholinesterase activity is induced when cells undergo apoptosis and that consequently there is a rise in the level of plasma acetylcholinesterase. - Highlights: > Acetylcholinesterase activity is induced by organophosphorus agents. > AChE induction is related to apoptosis. > Induction of AChE activity by OP is independent of BChE.

  16. Characterization of stationary and pulsed inductively coupled RF discharges for plasma sterilization

    NASA Astrophysics Data System (ADS)

    Gans, T.; Osiac, M.; O'Connell, D.; Kadetov, V. A.; Czarnetzki, U.; Schwarz-Selinger, T.; Halfmann, H.; Awakowicz, P.

    2005-05-01

    Sterilization of bio-medical materials using radio frequency (RF) excited inductively coupled plasmas (ICPs) has been investigated. A double ICP has been developed and studied for homogenous treatment of three-dimensional objects. Sterilization is achieved through a combination of ultraviolet light, ion bombardment and radical treatment. For temperature sensitive materials, the process temperature is a crucial parameter. Pulsing of the plasma reduces the time average heat strain and also provides additional control of the various sterilization mechanisms. Certain aspects of pulsed plasmas are, however, not yet fully understood. Phase resolved optical emission spectroscopy and time resolved ion energy analysis illustrate that a pulsed ICP ignites capacitively before reaching a stable inductive mode. Time resolved investigations of the post-discharge, after switching off the RF power, show that the plasma boundary sheath in front of a substrate does not fully collapse for the case of hydrogen discharges. This is explained by electron heating through super-elastic collisions with vibrationally excited hydrogen molecules.

  17. Resonant RF network antennas for large-area and large-volume inductively coupled plasma sources

    NASA Astrophysics Data System (ADS)

    Hollenstein, Ch; Guittienne, Ph; Howling, A. A.

    2013-10-01

    Large-area and large-volume radio frequency (RF) plasmas are produced by different arrangements of an elementary electrical mesh consisting of two conductors interconnected by a capacitor at each end. The obtained cylindrical and planar RF networks are resonant and generate very high RF currents. The input impedance of such RF networks shows the behaviour of an RLC parallel resonance equivalent circuit. The real impedance at the resonance frequency is of great advantage for power matching compared with conventional inductive devices. Changes in the RLC equivalent circuit during the observed E-H transition will allow future interpretation of the plasma-antenna coupling. Furthermore, high power transfer efficiencies are found during inductively coupled plasma (ICP) operation. For the planar RF antenna network it is shown that the E-H transition occurs simultaneously over the entire antenna. The underlying physics of these discharges induced by the resonant RF network antenna is found to be identical to that of the conventional ICP devices described in the literature. The resonant RF network antenna is a new versatile plasma source, which can be adapted to applications in industry and research.

  18. Analysis of tungsten carbide coatings by infrared laser-induced argon spark with inductively coupled plasma atomic emission spectrometry

    NASA Astrophysics Data System (ADS)

    Kanický, V.; Otruba, V.; Mermet, J.-M.

    2000-10-01

    Infrared laser ablation was studied for application to the analysis of plasma-sprayed tungsten carbide/cobalt coatings. The potential of the laser induced argon-spark (LINA-Spark™), as a sample introduction device in inductively coupled plasma atomic emission spectrometry was studied. The use of an IR laser along with defocusing led to laser-induced microplasma-based ablation. The mass ablation rate, represented by the ICP emission intensity per laser beam unit area, exhibited a flat increase in the irradiance range 2-250 GW/cm 2. A low slope (0.5) of this dependence in log-log scale gave evidence of plasma shielding. The steep increase in the measured acoustic signal when focused in front of the sample, i.e. in argon, indicated a breakdown of argon. Consequently, considerably lower ICP emissions were observed within the same range of irradiance. The cobalt/tungsten line intensity ratio in the ICP was practically constant from 1.5 up to at least 250 GW/cm 2. Acceptable precision (R.S.D.<5%) was obtained without internal standardization for irradiance between 2 and 8 GW/cm 2. Optimization of the laser pulse energy, repetition rate, beam focusing and sample displacement during interaction led to the linearization of dependences of signal vs. cobalt percentage, at least up to the highest studied value of 23% Co.

  19. Effect of antenna size on electron kinetics in inductively coupled plasmas

    SciTech Connect

    Lee, Hyo-Chang; Chung, Chin-Wook

    2013-10-15

    Spatially resolved measurements of electron energy distribution functions (EEDFs) are investigated in inductively coupled plasmas with two planar antenna coils. When the plasma is sustained by the antenna with a diameter of 18 cm, the nonlocal kinetics is preserved in the argon gas pressure range from 2 mTorr to 20 mTorr. However, electron kinetics transit from nonlocal kinetics to local kinetics in discharge sustained by the antenna coil with diameter 34 cm. The results suggest that antenna size as well as chamber length are important parameters for the transition of the electron kinetics. Spatial variations of plasma potential, effective electron temperature, and EEDF in terms of total electron energy scale are also presented.

  20. Callisto plasma interactions: Hybrid modeling including induction by a subsurface ocean

    NASA Astrophysics Data System (ADS)

    Lindkvist, Jesper; Holmström, Mats; Khurana, Krishan K.; Fatemi, Shahab; Barabash, Stas

    2015-06-01

    By using a hybrid plasma solver (ions as particles and electrons as a fluid), we have modeled the interaction between Callisto and Jupiter's magnetosphere for variable ambient plasma parameters. We compared the results with the magnetometer data from flybys (C3, C9, and C10) by the Galileo spacecraft. Modeling the interaction between Callisto and Jupiter's magnetosphere is important to establish the origin of the magnetic field perturbations observed by Galileo and thought to be related to a subsurface ocean. Using typical upstream magnetospheric plasma parameters and a magnetic dipole corresponding to the inductive response inside the moon, we show that the model results agree well with observations for the C3 and C9 flybys, but agrees poorly with the C10 flyby close to Callisto. The study does support the existence of a subsurface ocean at Callisto.

  1. Simulation and Experimental Measurements of Inductively Coupled CF4 and CF4/Ar Plasmas

    NASA Technical Reports Server (NTRS)

    Hash, D. B.; Bose, D.; Rao, M. V. V. S.; Cruden, B. A.; Meyyappan, M.; Sharma, S. P.; Arnold, James O. (Technical Monitor)

    2000-01-01

    The recently developed code SEMS (semiconductor equipment modeling software)is applied to the simulation of CF4 and CF4/Ar inductively coupled plasmas (ICP). This work builds upon the earlier nitrogen, transformer coupled plasma (TCP) SEMS research by demonstrating its accuracy for more complex reactive mixtures, moving closer to the realization of a virtual plasma reactor. Attention is given to the etching of and/or formation of carbonaceous films on the quartz dielectric window and diagnostic aperatures. The simulations are validated through comparisons with experimental measurements using FTIR (Fourier Transform Infrared) and UV absorption spectroscopy for CFx and SiFx neutral radicals, QMS (quadrupole mass spectrometry) for the ions, and Langmuir probe measurements of electron number density and temperature in an ICP GEC reference cell.

  2. Measurement of neutral gas temperature in a 13.56 MHz inductively coupled plasma

    SciTech Connect

    Jayapalan, Kanesh K.; Chin, Oi Hoong

    2015-04-24

    Measuring the temperature of neutrals in inductively coupled plasmas (ICP) is important as heating of neutral particles will influence plasma characteristics such as the spatial distributions of plasma density and electron temperature. Neutral gas temperatures were deduced using a non-invasive technique that combines gas actinometry, optical emission spectroscopy and simulation which is described here. Argon gas temperature in a 13.56 MHz ICP were found to fall within the range of 500 − 800 K for input power of 140 − 200 W and pressure of 0.05 − 0.2 mbar. Comparing spectrometers with 0.2 nm and 0.5 nm resolution, improved fitting sensitivity was observed for the 0.2 nm resolution.

  3. Synthesis of Ozone at Atmospheric Pressure by a Quenched Induction-Coupled Plasma Torch

    SciTech Connect

    A. Blutke; B.C. Stratton; D.R. Mikkelsen; J. Vavruska; R. Knight

    1998-01-01

    The technical feasibility of using an induction-coupled plasma (ICP) torch to synthesize ozone at atmospheric pressure is explored. Ozone concentrations up to ~250 ppm were produced using a thermal plasma reactor system based on an ICP torch operating at 2.5 MHz and ~11 kVA with an argon/oxygen mixture as the plasma-forming gas. A gaseous oxygen quench formed ozone by rapid mixing of molecular oxygen with atomic oxygen produced by the torch. The ozone concentration in the reaction chamber was measured by Fourier Transform infrared (FTIR) spectroscopy over a wide range of experimental configurations. The geometry of the quench gas flow, the quench flow velocity, and the quench flow rate played important roles in determining the ozone concentration. The ozone concentration was sensitive to the torch RF power, but was insensitive to the torch gas flow rates. These observations are interpreted within the framework of a simple model of ozone synthesis.

  4. A volume averaged global model for inductively coupled HBr/Ar plasma discharge

    NASA Astrophysics Data System (ADS)

    Chung, Sang-Young; Kwon, Deuk-Chul; Choi, Heechol; Song, Mi-Young

    2015-09-01

    A global model for inductively coupled HBr/Ar plasma was developed. The model was based on a self-consistent global model had been developed by Kwon et al., and a set of chemical reactions in the HBr/Ar plasma was compiled by surveying theoretical, experimental and evaluative researches. In this model vibrational excitations of bi-atomic molecules and electronic excitations of hydrogen atom were taken into account. Neutralizations by collisions between positive and negative ions were considered with Hakman's approximate formula achieved by fitting of theoretical result. For some reactions that were not supplied from literatures the reaction parameters of Cl2 and HCl were adopted as them Br2 and HBr, respectively. For validation calculation results using this model were compared with experimental results from literatures for various plasma discharge parameters and it showed overall good agreement.

  5. Altering the sulfur content in the propanethiol plasma polymers using the capacitive-to-inductive mode transition in inductively coupled plasma discharge

    SciTech Connect

    Thiry, Damien; Britun, Nikolay; Konstantinidis, Stephanos; Dauchot, Jean-Pierre; Denis, Laurent; Snyders, Rony

    2012-02-13

    The effect of the transition from capacitive (E) to inductive (H) mode on propanethiol plasma polymer films properties was investigated by optical emission as well as by x-ray photoelectron spectroscopy. The E mode is characterized by low deposition rate and by high sulfur content in the films ({approx}40% vs {approx}20% in H mode). After aging, a strong decrease of sulfur to carbon content (from {approx}0.75 to 0.13), attributed to desorption of unbounded sulfur-based molecules (e.g., H{sub 2}S), is detected at low power in E mode. The importance of the E-H transition for altering the film properties is highlighted.

  6. Altering the sulfur content in the propanethiol plasma polymers using the capacitive-to-inductive mode transition in inductively coupled plasma discharge

    NASA Astrophysics Data System (ADS)

    Thiry, Damien; Britun, Nikolay; Konstantinidis, Stephanos; Dauchot, Jean-Pierre; Denis, Laurent; Snyders, Rony

    2012-02-01

    The effect of the transition from capacitive (E) to inductive (H) mode on propanethiol plasma polymer films properties was investigated by optical emission as well as by x-ray photoelectron spectroscopy. The E mode is characterized by low deposition rate and by high sulfur content in the films (˜40% vs ˜20% in H mode). After aging, a strong decrease of sulfur to carbon content (from ˜0.75 to 0.13), attributed to desorption of unbounded sulfur-based molecules (e.g., H2S), is detected at low power in E mode. The importance of the E-H transition for altering the film properties is highlighted.

  7. Plasma sterilization of Geobacillus Stearothermophilus by O{mathsf2}:N{mathsf2} RF inductively coupled plasma

    NASA Astrophysics Data System (ADS)

    Kylián, O.; Sasaki, T.; Rossi, F.

    2006-05-01

    The aim of this work is to identify the main process responsible for sterilization of Geobacillus Stearothermophilus spores in O{2}:N{2} RF inductively coupled plasma. In order to meet this objective the sterilization efficiencies of discharges in mixtures differing in the initial O{2}/N{2} ratios are compared with plasma properties and with scanning electron microscopy images of treated spores. According to the obtained results it can be concluded that under our experimental conditions the time needed to reach complete sterilization is more related to O atom density than UV radiation intensity, i.e. complete sterilization is not related only to DNA damage as in UV sterilization but more likely to the etching of the spore.

  8. Initial Operation of the Miniaturized Inductively Heated Plasma Generator IPG6

    NASA Astrophysics Data System (ADS)

    Dropmann, Michael; Herdrich, Georg; Laufer, Rene; Koch, Helmut; Gomringer, Chris; Cook, Mike; Schmoke, Jimmy; Matthews, Lorin; Hyde, Truell

    2012-10-01

    In close collaboration between the Center for Astrophysics, Space Physics and Engineering Research (CASPER) at Baylor University, Texas, and the Institute of Space Systems (IRS) at the University of Stuttgart, Germany, two plasma wind tunnel facilities of similar type have been established using the inductively heated plasma source IPG6 which is based on proven IRS designs. The facility at Baylor University (IPG6-B) works at a frequency of 13.56 MHz and a maximum power of 15 kW. A vacuum pump of 160m^3/h in combination with a butterfly valve allows pressure control in a wide range. First experiments have been conducted with Air, O2 and N2 as working gases and volumetric flow rates of up to 14 L/min at pressures of a few 100 Pa, although pressures below 1 Pa are achievable at lower flow rates. The maximum tested electric power so far was 8 kW. Plasma powers and total pressures in the plasma jet have been obtained. In the near future the set up of additional diagnostics, the use of other gases (i.e. H2, He), and the integration of a dust particle accelerator are planned. The intended fields of research are basic investigation in thermo-chemistry and plasma radiation, space plasma environments and high heat fluxes e.g. in fusion devices or during atmospheric entry of spacecraft.

  9. Langmuir Probe Measurements of Inductively Coupled Plasmas in CF4/Ar/O2 Mixtures

    NASA Technical Reports Server (NTRS)

    Rao, M. V. V. S.; Meyyappan, M.; Sharma, S. P.

    2000-01-01

    Fluorocarbon gases, such as CF4, and their mixtures are widely used in contemporary low-pressure and high-density plasma processing techniques. In such plasmas Langmuir probe is one of the most commonly employed diagnostic techniques to obtain electron number density (ne), electron temperature (Te), electron energy distribution function (EEDF), mean electron energy (Ee), ion number density (ni), and plasma potential (Vp). In this paper we report probe data for planar inductively coupled plasmas in CF4/O2/Ar mixtures. By varying the relative concentrations in the mixture, radial profiles of ne, ni, Te, Ee, Vp, EEDF were measured in the mid-plane of the plasma at 10 mTorr and 20 mTorr of gas pressures, and 200 W and 300 W of RF powers. Data show that ne and ni decrease with increase of CF4 content and decrease of gas-pressure but they increase with increase of RF-power, whereas Vp increases with decrease of gas-pressure and remains independent of RF-power. However, they all peak at the center of the plasma and decrease towards the edge while Te follows the other way and increases a little with increase of power. The measured EEDFs exhibit Druyvesteyn-like distribution at all pressures and powers. Data are analyzed and will be presented.

  10. Langmuir Probe Distortions and Probe Compensation in an Inductively Coupled Plasma

    NASA Technical Reports Server (NTRS)

    Ji, J. S.; Cappelli, M. A.; Kim, J. S.; Rao, M. V. V. S.; Sharma, S. P.

    1999-01-01

    In many RF discharges, Langmuir probe measurements are usually made against a background of sinusoidal (and not so sinusoidal) fluctuations in the plasma parameters such as the plasma potential (Vp), the electron number density (ne), and the electron temperature (Te). The compensation of sinusoidal fluctuations in Vp has been extensively studied and is relatively well understood. Less attention has been paid to the possible distortions introduced by small fluctuations in plasma density and/or plasma temperature, which may arise in the sheath and pre-sheath regions of RF discharges. Here, we present the results of a model simulation of probe characteristics subject to fluctuations in both Vp and ne. The modeling of probe distortion due to possible fluctuations in Te is less straightforward. A comparison is presented of calculations with experimental measurements using a compensated and uncompensated Langmuir probe in an inductively coupled GEC reference cell plasma, operating on Ar and Ar/CF4 mixtures. The plasma parameters determined from the compensated probe characteristics are compared to previous measurements of others made in similar discharges, and to our own measurements of the average electron density derived from electrical impedance measurements.

  11. On anomalous temporal evolution of gas pressure in inductively coupled plasma

    SciTech Connect

    Seo, B. H.; Chang, H. Y.; You, S. J.; Kim, J. H.; Seong, D. J.

    2013-04-01

    The temporal measurement of gas pressure in inductive coupled plasma revealed that there is an interesting anomalous evolution of gas pressure in the early stage of plasma ignition and extinction: a sudden gas pressure change and its relaxation of which time scales are about a few seconds and a few tens of second, respectively, were observed after plasma ignition and extinction. This phenomenon can be understood as a combined result between the neutral heating effect induced by plasma and the pressure relaxation effect for new gas temperature. The temporal measurement of gas temperature by laser Rayleigh scattering and the time dependant calculations for the neutral heating and pressure relaxation are in good agreement with our experimental results. This result and physics behind are expected to provide a new operational perspective of the recent plasma processes of which time is very short, such as a plasma enhanced atomic layer deposition/etching, a soft etch for disposal of residual by-products on wafer, and light oxidation process in semiconductor manufacturing.

  12. Transport and trapping of dust particles in a potential well created by inductively coupled diffused plasmas.

    PubMed

    Choudhary, Mangilal; Mukherjee, S; Bandyopadhyay, P

    2016-05-01

    A versatile linear dusty (complex) plasma device is designed to study the transport and dynamical behavior of dust particles in a large volume. Diffused inductively coupled plasma is generated in the background of argon gas. A novel technique is used to introduce the dust particles in the main plasma by striking a secondary direct current glow discharge. These dust particles are found to get trapped in an electrostatic potential well, which is formed due to the combination of the ambipolar electric field caused by diffusive plasma and the field produced by the charged glass wall of the vacuum chamber. According to the requirements, the volume of the dust cloud can be controlled very precisely by tuning the plasma and discharge parameters. The present device can be used to address the underlying physics behind the transport of dust particles, self-excited dust acoustic waves, and instabilities. The detailed design of this device, plasma production and characterization, trapping and transport of the dust particle, and some of the preliminary experimental results are presented. PMID:27250421

  13. Transport and trapping of dust particles in a potential well created by inductively coupled diffused plasmas

    NASA Astrophysics Data System (ADS)

    Choudhary, Mangilal; Mukherjee, S.; Bandyopadhyay, P.

    2016-05-01

    A versatile linear dusty (complex) plasma device is designed to study the transport and dynamical behavior of dust particles in a large volume. Diffused inductively coupled plasma is generated in the background of argon gas. A novel technique is used to introduce the dust particles in the main plasma by striking a secondary direct current glow discharge. These dust particles are found to get trapped in an electrostatic potential well, which is formed due to the combination of the ambipolar electric field caused by diffusive plasma and the field produced by the charged glass wall of the vacuum chamber. According to the requirements, the volume of the dust cloud can be controlled very precisely by tuning the plasma and discharge parameters. The present device can be used to address the underlying physics behind the transport of dust particles, self-excited dust acoustic waves, and instabilities. The detailed design of this device, plasma production and characterization, trapping and transport of the dust particle, and some of the preliminary experimental results are presented.

  14. Characterization of Inductively Coupled Plasmas in High Power, High Pressure Regime

    NASA Astrophysics Data System (ADS)

    Wang, Jun-Chieh; Kenney, Jason; Agarwal, Ankur; Nichols, Michael; Rogers, James; Rauf, Shahid

    2015-09-01

    Inductively coupled plasmas (ICP) are widely used in the microelectronic industry for thin film etching. ICPs have typically been operated at low gas pressures (<50 mTorr) and they have been well-characterized in this regime. Several applications requiring high etch rates (e.g., vertical NAND etch) have recently extended the use of ICPs to the high power (>4000 W) and high pressure (>100 mTorr) regime. ICP operation in this high-power, high-pressure regime imposes a tremendous challenge of achieving good plasma uniformity over large substrates. This necessitates a good theoretical understanding of the underlying physics, thorough experimental characterization, and more accurate numerical models for hardware design guidance. In this study, we will focus on the characterization of ICP in the high-power, high-pressure regime. Computational modeling is done using CRTRS, our in-house 2D/3D plasma model. The fluid plasma model is coupled to a circuit model to self-consistently account for the capacitive coupling from the coils that is expected to dominate in this operating regime. Properties of Ar plasma will be discussed and compared with experiments. The impact of critical operating parameters such as ICP power, pressure, flow rate, and current ratio (in multi-coil antenna structures) on plasma characteristics will be examined. Results in relevant processing gases will also be discussed.

  15. Axially and radially viewed inductively coupled plasmas — a critical review

    NASA Astrophysics Data System (ADS)

    Brenner, I. B.; Zander, A. T.

    2000-08-01

    The present status of axially viewed inductively coupled plasmas (ICP) is reviewed with special emphasis placed on the analytical performance of currently available systems. Descriptions are given of the various designs of the plasma-spectrometer configuration. Conventional figures of merit such as limits of detection, background behavior, interferences due to easily ionized elements (EIE), Ca and acids, and the Mg II 280.270 nm/Mg I 285.213 nm intensity ratio, are used to compare the performance of axially viewed and radially viewed ICPs. Various modes of sample introduction, including conventional pneumatic and ultrasonic nebulization (USN), thermospray and a direct injection probe will be described. For axially viewed ICPs, limits of detection (LOD) are improved by factors varying from approximately 2 to 30. Additional improvements by factors of 2-20 can be obtained using USN. The improvement factors generally depend on energy potentials of the spectral lines and the element. Although limits of detection in the presence of Ca and Na are degraded relative to an aqueous solution 10-30-fold, USN LODs using an axially viewed ICP are improved relative to those obtained using a pneumatic nebulizer for solutions containing Ca and Na. With normal aerosol load and under robust plasma conditions (as evidenced by Mg II/Mg I intensity ratios >8), EIE, Ca and mineral acid induced interferences are relatively small and are similar in axial and conventional radial configurations. However, interferences due to Ca are larger than those caused by Na due to the larger amount of energy required to dissociate the matrix. Matrix effects increase considerably when an USN is employed. For robust plasmas, ICP operating conditions and performance for multi-element quantitative analysis do not differ significantly from those of conventional radial configurations. In cases where robustness decreases, matrix interferences should be taken into account when establishing optimum conditions for

  16. Jovian Plasmas Torus Interaction with Europa. Plasma Wake Structure and Effect of Inductive Magnetic Field: 3D Hybrid Kinetic Simulation

    NASA Technical Reports Server (NTRS)

    Lipatov, A. S.; Cooper, J F.; Paterson, W. R.; Sittler, E. C., Jr.; Hartle, R. E.; Simpson, David G.

    2013-01-01

    The hybrid kinetic model supports comprehensive simulation of the interaction between different spatial and energetic elements of the Europa moon-magnetosphere system with respect to a variable upstream magnetic field and flux or density distributions of plasma and energetic ions, electrons, and neutral atoms. This capability is critical for improving the interpretation of the existing Europa flyby measurements from the Galileo Orbiter mission, and for planning flyby and orbital measurements (including the surface and atmospheric compositions) for future missions. The simulations are based on recent models of the atmosphere of Europa (Cassidy et al., 2007; Shematovich et al., 2005). In contrast to previous approaches with MHD simulations, the hybrid model allows us to fully take into account the finite gyroradius effect and electron pressure, and to correctly estimate the ion velocity distribution and the fluxes along the magnetic field (assuming an initial Maxwellian velocity distribution for upstream background ions). Photoionization, electron-impact ionization, charge exchange and collisions between the ions and neutrals are also included in our model. We consider the models with Oþ þ and Sþ þ background plasma, and various betas for background ions and electrons, and pickup electrons. The majority of O2 atmosphere is thermal with an extended non-thermal population (Cassidy et al., 2007). In this paper, we discuss two tasks: (1) the plasma wake structure dependence on the parameters of the upstream plasma and Europa's atmosphere (model I, cases (a) and (b) with a homogeneous Jovian magnetosphere field, an inductive magnetic dipole and high oceanic shell conductivity); and (2) estimation of the possible effect of an induced magnetic field arising from oceanic shell conductivity. This effect was estimated based on the difference between the observed and modeled magnetic fields (model II, case (c) with an inhomogeneous Jovian magnetosphere field, an inductive

  17. Plasma Interaction with International Space Station High Voltage Solar Arrays

    NASA Technical Reports Server (NTRS)

    Heard, John W.

    2002-01-01

    The International Space Station (ISS) is presently being assembled in low-earth orbit (LEO) operating high voltage solar arrays (-160 V max, -140 V typical with respect to the ambient atmosphere). At the station's present altitude, there exists substantial ambient plasma that can interact with the solar arrays. The biasing of an object to an electric potential immersed in plasma creates a plasma "sheath" or non-equilibrium plasma around the object to mask out the electric fields. A positively biased object can collect electrons from the plasma sheath and the sheath will draw a current from the surrounding plasma. This parasitic current can enter the solar cells and effectively "short out" the potential across the cells, reducing the power that can be generated by the panels. Predictions of collected current based on previous high voltage experiments (SAMPIE (Solar Array Module Plasma Interactions Experiment), PASP+ (Photovoltaic Array Space Power) were on the order of amperes of current. However, present measurements of parasitic current are on the order of several milliamperes, and the current collection mainly occurs during an "eclipse exit" event, i.e., when the space station comes out of darkness. This collection also has a time scale, t approx. 1000 s, that is much slower than any known plasma interaction time scales. The reason for the discrepancy between predictions and present electron collection is not understood and is under investigation by the PCU (Plasma Contactor Unit) "Tiger" team. This paper will examine the potential structure within and around the solar arrays, and the possible causes and reasons for the electron collection of the array.

  18. Study on the O2 Plasma Treatment of Indium Tin Oxide for Organic Light Emitting Diodes Using Inductively Coupled Plasma

    NASA Astrophysics Data System (ADS)

    Jeong, Chang Hyun; Lee, June Hee; Lim, Jong Hyeuk; Lim, Jong Tae; Yeom, Geun Young

    2006-04-01

    In this study, the effect of O2 inductively coupled plasma (ICP) conditions for the indium tin oxide (ITO) surface treatment on the organic light emitting diode (OLED) device performances were investigated. By the O2 plasma treatment of ITO glass, better OLED device performances such as a lower turn-on voltage, a higher luminescence, and a higher power efficiency could be obtained and the use of lower oxygen pressure and higher ICP power improved the device properties further. DC-biasing of the ITO glass substrate degraded the device properties. The use of lower oxygen pressure and higher ICP power increased the densities of O2+ and O* in the plasma, and the plasma-treated ITO surface showed a lower carbon, a higher O/(Sn+In), and a higher Sn4+/In for the condition of lower oxygen pressure and higher ICP power. The improved OLED device properties with the ITO treated at the higher ICP power and the lower pressure appear to be from the increased hole injection to the OLED materials by decreasing the resistance of ITO and by increasing the work function of the ITO.

  19. Correlation between vibrational temperature of N2 and plasma parameters in inductively coupled Ar/N2 plasmas

    NASA Astrophysics Data System (ADS)

    Kim, Young-Cheol; Lee, Hyo-Chang; Kim, Yu-Sin; Chung, Chin-Wook

    2015-08-01

    Vibrational temperature (Tvib) of N2 gas and electron energy distribution function (EEDF) were measured in Ar/N2 mixture inductively coupled plasma (ICP). At a low gas pressure of 5 mTorr where the EEDF is bi-Maxwellian distribution, plasma density np and Tvib (from 7000 K to 5600 K) slightly decrease. However, remarkable decrease in np and Tvib is found with the dilution of N2 gas at a high gas pressure of 50 mTorr, where the EEDF is depleted Maxwellian distribution at a fixed ICP power of 150 W. When the ICP power increases from 150 W to 300 W at the gas pressure of 50 mTorr, the depleted tail on the EEDF is replenished, while np is little changed with the dilution of N2 gas. In this case, Tvib slightly decreases from 9500 K to 7600 K. These results indicate that the variation of Tvib is strongly correlated to the plasma parameters, such as the plasma density and EEDF.

  20. Bulk plasma fragmentation in a C{sub 4}F{sub 8} inductively coupled plasma: A hybrid modeling study

    SciTech Connect

    Zhao, Shu-Xia; Zhang, Yu-Ru; Gao, Fei; Wang, You-Nian; Bogaerts, Annemie

    2015-06-28

    A hybrid model is used to investigate the fragmentation of C{sub 4}F{sub 8} inductive discharges. Indeed, the resulting reactive species are crucial for the optimization of the Si-based etching process, since they determine the mechanisms of fluorination, polymerization, and sputtering. In this paper, we present the dissociation degree, the density ratio of F vs. C{sub x}F{sub y} (i.e., fluorocarbon (fc) neutrals), the neutral vs. positive ion density ratio, details on the neutral and ion components, and fractions of various fc neutrals (or ions) in the total fc neutral (or ion) density in a C{sub 4}F{sub 8} inductively coupled plasma source, as well as the effect of pressure and power on these results. To analyze the fragmentation behavior, the electron density and temperature and electron energy probability function (EEPF) are investigated. Moreover, the main electron-impact generation sources for all considered neutrals and ions are determined from the complicated C{sub 4}F{sub 8} reaction set used in the model. The C{sub 4}F{sub 8} plasma fragmentation is explained, taking into account many factors, such as the EEPF characteristics, the dominance of primary and secondary processes, and the thresholds of dissociation and ionization. The simulation results are compared with experiments from literature, and reasonable agreement is obtained. Some discrepancies are observed, which can probably be attributed to the simplified polymer surface kinetics assumed in the model.

  1. Internal Kink Mode Dynamics in High-beta NSTX Plasmas

    SciTech Connect

    J.E. Menard; R.E. Bell; E.D. Fredrickson; D.A. Gates; S.M. Kaye; B.P. LeBlanc; S.S. Medley; W. Park; S.A. Sabbagh; A. Sontag; D. Stutman; K. Tritz; W. Zhu; the NSTX Research Team

    2004-12-22

    Saturated internal kink modes have been observed in many of the highest toroidal {beta} discharges of the National Spherical Torus Experiment (NSTX). These modes often cause rotation flattening in the plasma core, can degrade energy confinement, and in some cases contribute to the complete loss of plasma angular momentum and stored energy. Characteristics of the modes are measured using soft X-ray, kinetic profile, and magnetic diagnostics. Toroidal flows approaching Alfvenic speeds, island pressure peaking, and enhanced viscous and diamagnetic effects associated with high-{beta} may contribute to mode nonlinear stabilization. These saturation mechanisms are investigated for NSTX parameters and compared to experimental data.

  2. The Relation of Parental Guilt Induction to Child Internalizing Problems When a Caregiver Has a History of Depression.

    PubMed

    Rakow, Aaron; Forehand, Rex; McKee, Laura; Coffelt, Nicole; Champion, Jennifer; Fear, Jessica; Compas, Bruce

    2009-08-01

    The purpose of this study was to examine the relation between parental guilt induction and child internalizing problems in families where a caregiver had experienced depression. A total of 107 families, including 146 children (age 9-15), participated. Child-reported parental guilt induction, as well as three more traditionally studied parenting behaviors (warmth/involvement, monitoring, and discipline), were assessed, as was parent-report of child internalizing problem behavior. Linear Mixed Models Analysis indicated parental guilt induction was positively related to child internalizing problems in the context of the remaining three parenting behaviors. Implications of the findings for prevention and intervention parenting programs are considered. PMID:20090863

  3. The Relation of Parental Guilt Induction to Child Internalizing Problems When a Caregiver Has a History of Depression

    PubMed Central

    Rakow, Aaron; McKee, Laura; Coffelt, Nicole; Champion, Jennifer; Fear, Jessica; Compas, Bruce

    2009-01-01

    The purpose of this study was to examine the relation between parental guilt induction and child internalizing problems in families where a caregiver had experienced depression. A total of 107 families, including 146 children (age 9–15), participated. Child-reported parental guilt induction, as well as three more traditionally studied parenting behaviors (warmth/involvement, monitoring, and discipline), were assessed, as was parent-report of child internalizing problem behavior. Linear Mixed Models Analysis indicated parental guilt induction was positively related to child internalizing problems in the context of the remaining three parenting behaviors. Implications of the findings for prevention and intervention parenting programs are considered. PMID:20090863

  4. Axially and radially viewed inductively coupled plasmas — a critical review

    NASA Astrophysics Data System (ADS)

    Brenner, I. B.; Zander, A. T.

    2000-08-01

    The present status of axially viewed inductively coupled plasmas (ICP) is reviewed with special emphasis placed on the analytical performance of currently available systems. Descriptions are given of the various designs of the plasma-spectrometer configuration. Conventional figures of merit such as limits of detection, background behavior, interferences due to easily ionized elements (EIE), Ca and acids, and the Mg II 280.270 nm/Mg I 285.213 nm intensity ratio, are used to compare the performance of axially viewed and radially viewed ICPs. Various modes of sample introduction, including conventional pneumatic and ultrasonic nebulization (USN), thermospray and a direct injection probe will be described. For axially viewed ICPs, limits of detection (LOD) are improved by factors varying from approximately 2 to 30. Additional improvements by factors of 2-20 can be obtained using USN. The improvement factors generally depend on energy potentials of the spectral lines and the element. Although limits of detection in the presence of Ca and Na are degraded relative to an aqueous solution 10-30-fold, USN LODs using an axially viewed ICP are improved relative to those obtained using a pneumatic nebulizer for solutions containing Ca and Na. With normal aerosol load and under robust plasma conditions (as evidenced by Mg II/Mg I intensity ratios >8), EIE, Ca and mineral acid induced interferences are relatively small and are similar in axial and conventional radial configurations. However, interferences due to Ca are larger than those caused by Na due to the larger amount of energy required to dissociate the matrix. Matrix effects increase considerably when an USN is employed. For robust plasmas, ICP operating conditions and performance for multi-element quantitative analysis do not differ significantly from those of conventional radial configurations. In cases where robustness decreases, matrix interferences should be taken into account when establishing optimum conditions for

  5. Tin removal from extreme ultraviolet collector optics by inductively coupled plasma reactive ion etching

    SciTech Connect

    Shin, H.; Srivastava, S. N.; Ruzic, D. N.

    2008-05-15

    Tin (Sn) has the advantage of delivering higher conversion efficiency compared to other fuel materials (e.g., Xe or Li) in an extreme ultraviolet (EUV) source, a necessary component for the leading next generation lithography. However, the use of a condensable fuel in a lithography system leads to some additional challenges for maintaining a satisfactory lifetime of the collector optics. A critical issue leading to decreased mirror lifetime is the buildup of debris on the surface of the primary mirror that comes from the use of Sn in either gas discharge produced plasma (GDPP) or laser produced plasma (LPP). This leads to a decreased reflectivity from the added material thickness and increased surface roughness that contributes to scattering. Inductively coupled plasma reactive ion etching with halide ions is one potential solution to this problem. This article presents results for etch rate and selectivity of Sn over SiO{sub 2} and Ru. The Sn etch rate in a chlorine plasma is found to be much higher (of the order of hundreds of nm/min) than the etch rate of other materials. A thermally evaporated Sn on Ru sample was prepared and cleaned using an inductively coupled plasma etching method. Cleaning was confirmed using several material characterization techniques. Furthermore, a collector mock-up shell was then constructed and etching was performed on Sn samples prepared in a Sn EUV source using an optimized etching recipe. The sample surface before and after cleaning was analyzed by atomic force microscopy, x-ray photoelectron spectroscopy, and Auger electron spectroscopy. The results show the dependence of etch rate on the location of Sn samples placed on the collector mock-up shell.

  6. Inductive pulsed plasma thruster model with time-evolution of energy and state properties

    NASA Astrophysics Data System (ADS)

    Polzin, K. A.; Sankaran, K.; Ritchie, A. G.; Reneau, J. P.

    2013-11-01

    A model for pulsed inductive plasma acceleration is presented that consists of a set of circuit equations coupled to both a one-dimensional (1D) equation of motion and an equation governing the partitioning of energy. The latter two equations are obtained for the plasma current sheet by treating it as a single element of finite volume and integrating the governing equations over that volume. The integrated terms are replaced where necessary by physically equivalent approximations that are calculated through the solution of other parts of the governing equation set. The model improves upon previous 1D performance models by permitting the time-evolution of the temperature consistent with the time-varying energy flux into the plasma. The plasma state properties are also more realistically modelled and evolved in time, allowing for the tailoring of the model to different gases that may be chosen as propellants. Computational results for argon propellant are presented to demonstrate the efficacy of the model. The model produces a result where efficiency is maximized at a given value of the electrodynamic scaling term known as the dynamic impedance parameter. The scaling of different energy sinks as a function of the dynamic impedance parameter provides insight into the global energy partitioning in these types of accelerators. Results from the present model deviate from the previous version where temperature is selected as an input without regard for the energy that would be deposited to heat the gas to that temperature. Qualitatively and quantitatively, the model predicts specific impulse values that compare favourably with those measured for two separate inductive pulsed plasma thrusters. Efficiency is underpredicted in the regime where data are available, but the trends in the data and simulations follow similar trajectories that appear to be converging towards a predicted peak efficiency as the dynamic impedance parameter is increased.

  7. Numerical Modeling and Testing of an Inductively-Driven and High-Energy Pulsed Plasma Thrusters

    NASA Technical Reports Server (NTRS)

    Parma, Brian

    2004-01-01

    Pulsed Plasma Thrusters (PPTs) are advanced electric space propulsion devices that are characterized by simplicity and robustness. They suffer, however, from low thrust efficiencies. This summer, two approaches to improve the thrust efficiency of PPTs will be investigated through both numerical modeling and experimental testing. The first approach, an inductively-driven PPT, uses a double-ignition circuit to fire two PPTs in succession. This effectively changes the PPTs configuration from an LRC circuit to an LR circuit. The LR circuit is expected to provide better impedance matching and improving the efficiency of the energy transfer to the plasma. An added benefit of the LR circuit is an exponential decay of the current, whereas a traditional PPT s under damped LRC circuit experiences the characteristic "ringing" of its current. The exponential decay may provide improved lifetime and sustained electromagnetic acceleration. The second approach, a high-energy PPT, is a traditional PPT with a variable size capacitor bank. This PPT will be simulated and tested at energy levels between 100 and 450 joules in order to investigate the relationship between efficiency and energy level. Arbitrary Coordinate Hydromagnetic (MACH2) code is used. The MACH2 code, designed by the Center for Plasma Theory and Computation at the Air Force Research Laboratory, has been used to gain insight into a variety of plasma problems, including electric plasma thrusters. The goals for this summer include numerical predictions of performance for both the inductively-driven PPT and high-energy PFT, experimental validation of the numerical models, and numerical optimization of the designs. These goals will be met through numerical and experimental investigation of the PPTs current waveforms, mass loss (or ablation), and impulse bit characteristics.

  8. Enhanced current flow through a plasma cloud by induction of plasma turbulence

    NASA Technical Reports Server (NTRS)

    Hastings, D. E.

    1987-01-01

    Electrodynamic tethers have been proposed as a means of generating power in low earth orbit. One of the limitations on the power generated is the relatively low electron current that can be collected. It is proposed that the electron current can be significantly enhanced by means of current-induced plasma turbulence in a plasma cloud around the collecting anode. This is examined for the specific case of ion acoustic turbulence. An important conclusion is that the use of plasma clouds in the ionosphere will entail a high-impedance (no instability) and a low-impedance (ion acoustic instability) mode of operation. The low-impedance mode of operation will have two submodes, one steady state and one pulsed.

  9. Oscillating plasma bubbles. III. Internal electron sources and sinks

    SciTech Connect

    Stenzel, R. L.; Urrutia, J. M.

    2012-08-15

    An internal electron source has been used to neutralize ions injected from an ambient plasma into a spherical grid. The resultant plasma is termed a plasma 'bubble.' When the electron supply from the filament is reduced, the sheath inside the bubble becomes unstable. The plasma potential of the bubble oscillates near but below the ion plasma frequency. Different modes of oscillations have been observed as well as a subharmonic and multiple harmonics. The frequency increases with ion density and decreases with electron density. The peak amplitude occurs for an optimum current and the instability is quenched at large electron densities. The frequency also increases if Langmuir probes inside the bubble draw electrons. Allowing electrons from the ambient plasma to enter, the bubble changes the frequency dependence on grid voltage. It is concluded that the net space charge density in the sheath determines the oscillation frequency. It is suggested that the sheath instability is caused by ion inertia in an oscillating sheath electric field which is created by ion bunching.

  10. Computational hydrodynamics and optical performance of inductively-coupled plasma adaptive lenses

    NASA Astrophysics Data System (ADS)

    Mortazavi, M.; Urzay, J.; Mani, A.

    2015-06-01

    This study addresses the optical performance of a plasma adaptive lens for aero-optical applications by using both axisymmetric and three-dimensional numerical simulations. Plasma adaptive lenses are based on the effects of free electrons on the phase velocity of incident light, which, in theory, can be used as a phase-conjugation mechanism. A closed cylindrical chamber filled with Argon plasma is used as a model lens into which a beam of light is launched. The plasma is sustained by applying a radio-frequency electric current through a coil that envelops the chamber. Four different operating conditions, ranging from low to high powers and induction frequencies, are employed in the simulations. The numerical simulations reveal complex hydrodynamic phenomena related to buoyant and electromagnetic laminar transport, which generate, respectively, large recirculating cells and wall-normal compression stresses in the form of local stagnation-point flows. In the axisymmetric simulations, the plasma motion is coupled with near-wall axial striations in the electron-density field, some of which propagate in the form of low-frequency traveling disturbances adjacent to vortical quadrupoles that are reminiscent of Taylor-Görtler flow structures in centrifugally unstable flows. Although the refractive-index fields obtained from axisymmetric simulations lead to smooth beam wavefronts, they are found to be unstable to azimuthal disturbances in three of the four three-dimensional cases considered. The azimuthal striations are optically detrimental, since they produce high-order angular aberrations that account for most of the beam wavefront error. A fourth case is computed at high input power and high induction frequency, which displays the best optical properties among all the three-dimensional simulations considered. In particular, the increase in induction frequency prevents local thermalization and leads to an axisymmetric distribution of electrons even after introduction of

  11. Computational hydrodynamics and optical performance of inductively-coupled plasma adaptive lenses

    SciTech Connect

    Mortazavi, M.; Urzay, J. Mani, A.

    2015-06-15

    This study addresses the optical performance of a plasma adaptive lens for aero-optical applications by using both axisymmetric and three-dimensional numerical simulations. Plasma adaptive lenses are based on the effects of free electrons on the phase velocity of incident light, which, in theory, can be used as a phase-conjugation mechanism. A closed cylindrical chamber filled with Argon plasma is used as a model lens into which a beam of light is launched. The plasma is sustained by applying a radio-frequency electric current through a coil that envelops the chamber. Four different operating conditions, ranging from low to high powers and induction frequencies, are employed in the simulations. The numerical simulations reveal complex hydrodynamic phenomena related to buoyant and electromagnetic laminar transport, which generate, respectively, large recirculating cells and wall-normal compression stresses in the form of local stagnation-point flows. In the axisymmetric simulations, the plasma motion is coupled with near-wall axial striations in the electron-density field, some of which propagate in the form of low-frequency traveling disturbances adjacent to vortical quadrupoles that are reminiscent of Taylor-Görtler flow structures in centrifugally unstable flows. Although the refractive-index fields obtained from axisymmetric simulations lead to smooth beam wavefronts, they are found to be unstable to azimuthal disturbances in three of the four three-dimensional cases considered. The azimuthal striations are optically detrimental, since they produce high-order angular aberrations that account for most of the beam wavefront error. A fourth case is computed at high input power and high induction frequency, which displays the best optical properties among all the three-dimensional simulations considered. In particular, the increase in induction frequency prevents local thermalization and leads to an axisymmetric distribution of electrons even after introduction of

  12. Inductive Measurement of Plasma Jet Electrical Conductivity (MSFC Center Director's discretionary Fund). Part 2

    NASA Technical Reports Server (NTRS)

    Turner, M. W.; Hawk, C. W.; Litchford, R. J.

    2001-01-01

    Measurement of plasma jet electrical conductivity has utility in the development of explosively driven magnetohydrodynamic (MHD) energy converters as well as magnetic flux compression reaction chambers for nuclear/chemical pulse propulsion and power. Within these types of reactors, the physical parameter of critical importance to underlying MHD processes is the magnetic Reynolds number, the value of which depends upon the product of plasma electrical conductivity and velocity. Therefore, a thorough understanding of MHD phenomena at high magnetic Reynolds number is essential, and methods are needed for the accurate and reliable measurement of electrical conductivity in high-speed plasma jets. It is well known that direct measurements using electrodes suffer from large surface resistance, and an electrodeless technique is desired. To address this need, an inductive probing scheme, originally developed for shock tube studies, has been adapted. In this method, the perturbation of an applied magnetic field by a plasma jet induces a voltage in a search coil, which, in turn, can be used to infer electrical conductivity through the inversion of a Fredholm integral equation of the first kind. A 1-in.-diameter probe using a light-gas gun. Exploratory laboratory experiments were carried out using plasma jets expelled from 15-g shaped charges. Measured conductivities were in the range of 4 kS/m for unseeded octol charges and 26 kS/m for seeded octol charges containing 2-percent potassium carbonate by mass.

  13. Extraction and neutralization of positive and negative ions from a pulsed electronegative inductively coupled plasma

    NASA Astrophysics Data System (ADS)

    Marinov, D.; el Otell, Z.; Bowden, M. D.; Braithwaite, N. St. J.

    2015-12-01

    Almost electron-free (ion-ion) plasmas can be transiently formed during the afterglow phase of pulsed plasmas in electronegative gases. In ion-ion plasmas, both positive and negative ions can be extracted which makes them advantageous for a number of applications. In this paper, we investigate the extraction and acceleration of positive and negative ion beams from a pulsed inductively coupled plasma in SF6. The plasma is bounded by two electrodes biased synchronously with the discharge modulation. It is shown that when a DC bias voltage is applied during the afterglow phase, positive/negative ions are accelerated in a positive/negative space charge sheath formed in front of one of the electrodes. The energy of extracted ions closely follows the amplitude of the applied bias voltage (25-150 V) and the peak beam current density reaches 2 A m-2. With a view to using the described system as a source of energetic neutral beams for low damage material processing, simultaneous extraction and surface neutralization of positive and negative ions using an extraction electrode with high aspect ratio apertures is investigated.

  14. Kinetic modeling of E-to-H mode transition in inductively coupled hydrogen plasmas

    NASA Astrophysics Data System (ADS)

    Nishida, K.; Mattei, S.; Mochizuki, S.; Lettry, J.; Hatayama, A.

    2016-06-01

    Radio Frequency (RF) Inductively Coupled Plasmas (ICPs) are widely known for their two discharge modes, i.e., H-mode and E-mode, where the dynamics of the plasmas are completely different from each other. We have performed a kinetic simulation of a hydrogen plasma discharge in order to clarify the discharge mechanism and the E-to-H transition of the RF ICPs. The numerical simulation results, such as the time variations of spatial distribution of electron density and the power dissipated in the plasma, show the characteristic changes of the plasma dynamics due to E-to-H mode transition. Especially, the drastic change during the mode transition has been observed in the time evolution of the electron energy distribution function (EEDF). The EEDF deviates from a Maxwellian distribution before/after the transition and the deviation is more significant in the E-mode phase. These results indicate the importance of kinetic modeling for the physical understanding of E-to-H transition.

  15. Nitrogen Gas Plasma Generated by a Static Induction Thyristor as a Pulsed Power Supply Inactivates Adenovirus

    PubMed Central

    Sakudo, Akikazu; Toyokawa, Yoichi; Imanishi, Yuichiro

    2016-01-01

    Adenovirus is one of the most important causative agents of iatrogenic infections derived from contaminated medical devices or finger contact. In this study, we investigated whether nitrogen gas plasma, generated by applying a short high-voltage pulse to nitrogen using a static induction thyristor power supply (1.5 kilo pulse per second), exhibited a virucidal effect against adenoviruses. Viral titer was reduced by one log within 0.94 min. Results from detection of viral capsid proteins, hexon and penton, by Western blotting and immunochromatography were unaffected by the plasma treatment. In contrast, analysis using the polymerase chain reaction suggested that plasma treatment damages the viral genomic DNA. Reactive chemical products (hydrogen peroxide, nitrate, and nitrite), ultraviolet light (UV-A) and slight temperature elevations were observed during the operation of the gas plasma device. Viral titer versus intensity of each potential virucidal factor were used to identify the primary mechanism of disinfection of adenovirus. Although exposure to equivalent levels of UV-A or heat treatment did not inactivate adenovirus, treatment with a relatively low concentration of hydrogen peroxide efficiently inactivated the virus. Our results suggest the nitrogen gas plasma generates reactive chemical products that inactivate adenovirus by damaging the viral genomic DNA. PMID:27322066

  16. Methods for detecting and correcting inaccurate results in inductively coupled plasma-atomic emission spectrometry

    DOEpatents

    Chan, George C. Y.; Hieftje, Gary M.

    2010-08-03

    A method for detecting and correcting inaccurate results in inductively coupled plasma-atomic emission spectrometry (ICP-AES). ICP-AES analysis is performed across a plurality of selected locations in the plasma on an unknown sample, collecting the light intensity at one or more selected wavelengths of one or more sought-for analytes, creating a first dataset. The first dataset is then calibrated with a calibration dataset creating a calibrated first dataset curve. If the calibrated first dataset curve has a variability along the location within the plasma for a selected wavelength, errors are present. Plasma-related errors are then corrected by diluting the unknown sample and performing the same ICP-AES analysis on the diluted unknown sample creating a calibrated second dataset curve (accounting for the dilution) for the one or more sought-for analytes. The cross-over point of the calibrated dataset curves yields the corrected value (free from plasma related errors) for each sought-for analyte.

  17. Introduction of organic solvents into inductively coupled plasmas by ultrasonic nebulization with cryogenic desolvation

    SciTech Connect

    Wiederin, D.R.; Houk, R.S.; Winge, R.K.; D'Silva, A.P. )

    1990-06-01

    A two-step desolvation system for a continuous-flow ultrasonic nebulizer reduced the solvent load on an argon inductively coupled plasma (ICP). The aerosol was first heated above the boiling point of the solvent. Subsequently, solvent vapor was removed in two condensers kept at {minus}10{degree}C and {approx equal}{minus}80{degree}C. No special plasma ignition procedures were required; a change of solvent did not cause plasma instability. The plasma was stable to a forward power as low as 0.5 kW when methanol, acetone, acetonitrile, or ethanol was nebulized. The plasma could not be sustained while organic solvents were ultrasonically nebulized without at least partial desolvation. Detection limits for metals ranged from 0.2 {mu}g L{sup {minus}1} for Fe to 5 {mu}g L{sup {minus}1} for Pb. The detection limits for each element were approximately the same regardless of the organic solvent used and were comparable to those obtained during ultrasonic nebulization of aqueous solutions. With a forward power of 1.0 kW, molecular band emission from C{sub 2} was about 25 times less than when the aerosol was partially desolvated using a condensation temperature of {minus}10{degree}C.

  18. Nitrogen Gas Plasma Generated by a Static Induction Thyristor as a Pulsed Power Supply Inactivates Adenovirus.

    PubMed

    Sakudo, Akikazu; Toyokawa, Yoichi; Imanishi, Yuichiro

    2016-01-01

    Adenovirus is one of the most important causative agents of iatrogenic infections derived from contaminated medical devices or finger contact. In this study, we investigated whether nitrogen gas plasma, generated by applying a short high-voltage pulse to nitrogen using a static induction thyristor power supply (1.5 kilo pulse per second), exhibited a virucidal effect against adenoviruses. Viral titer was reduced by one log within 0.94 min. Results from detection of viral capsid proteins, hexon and penton, by Western blotting and immunochromatography were unaffected by the plasma treatment. In contrast, analysis using the polymerase chain reaction suggested that plasma treatment damages the viral genomic DNA. Reactive chemical products (hydrogen peroxide, nitrate, and nitrite), ultraviolet light (UV-A) and slight temperature elevations were observed during the operation of the gas plasma device. Viral titer versus intensity of each potential virucidal factor were used to identify the primary mechanism of disinfection of adenovirus. Although exposure to equivalent levels of UV-A or heat treatment did not inactivate adenovirus, treatment with a relatively low concentration of hydrogen peroxide efficiently inactivated the virus. Our results suggest the nitrogen gas plasma generates reactive chemical products that inactivate adenovirus by damaging the viral genomic DNA. PMID:27322066

  19. High Internal Inductance for High βN Steady-State Tokamak Operation

    NASA Astrophysics Data System (ADS)

    Ferron, J. R.

    2015-11-01

    An attractive scenario for steady-state tokamak operation at relatively high values of the internal inductance, li > 1 , has been demonstrated at DIII-D. The more peaked current density profile leads to reduced core energy transport and higher ideal stability limits that could eliminate the need for n >= 1 active stabilization coils at βN ~ 4, or enable βN ~ 5 with wall stabilization. The scenario's potential is shown by discharges at li ~ 1.3 with high bootstrap current fraction fBS ~0.8 , high plasma pressure βN ~ 5 and excellent confinement H98 (y , 2) ~ 1.8. This very high βN discharge with q95 =7.5 has noninductive current fraction fNI > 1 and too much bootstrap current in the H-mode pedestal, so li decreases with time. To achieve a stationary current profile, the key is to maximize βN and fBS while maintaining li high enough for stability through choice of q95 or by reduced pedestal current. DIII-D modeling shows that with q95 reduced to lower fBS to ~ 0.5, a self-consistent equilibrium has li ~ 1.07 and βN ~ 4 (below the n=1 no-wall limit) with q95 ~ 6. The remainder of the current can be externally-driven near the axis where the efficiency is high. Discharge tests with similar li in the ITER shape at q95=4.8 have reached fNI=0.7, fBS=0.4 at βN ~ 3.5 with performance appropriate for the ITER Q=5 mission, H89βN /q952~ 0.3. The li was shown to increase further above 1, to enable higher self-consistent fBS and βN, by reducing pedestal pressure and bootstrap current density through application of n = 3 resonant magnetic fields. With similar fields for ELM mitigation, and neutral beam and electron cyclotron current drive sources for near-axis current drive, the high li scenario is a potential option for ITER. The increased core confinement can help mitigate the effect of reduced pedestal pressure. Supported by US DOE under DE-FC02-04ER54698.

  20. Comparison of various interpretation methods of the electric probe measurements in inductively coupled Ar and O{sub 2} plasmas

    SciTech Connect

    Woo Seo, Min; Keun Bae, Min; Chung, T. H.

    2014-02-15

    In low-pressure inductively coupled argon and oxygen discharges, the plasma density and electron temperature and the electron energy distribution function (EEDF) were obtained by using a cylindrical electric probe. The plasma densities were determined by various methods to interpret the probe current-voltage characteristic curve: the EEDF integration, the electron saturation current, the ion current at the floating potential, and the orbital-motion-limited (OML) ion current. Quite a good agreement exists between the plasma densities determined by various classical methods. Although the probe technique has some limitation in electronegative plasmas, the plasma densities determined from OML theory compare well with those measured by the ion saturation current at the floating potential in the oxygen discharges. In addition, the EEDFs of inductively coupled Ar and oxygen plasmas are observed to be nearly Maxwellian at the pressure range of 1-40 mTorr.

  1. Chemical recoveries of technetium-99 for various procedures using inductively coupled plasma-mass spectrometry

    SciTech Connect

    Ihsanullah; East, B.W.

    1993-12-31

    The procedure for the determination of {sup 99}Tc inductively coupled plasma-mass spectrometry (ICP-MS) was based on the modification of a variety of available separation techniques. Standard Ru and Rh solutions were used for checking decontaminations and instrument response respectively. Technetium-99 and {sup 95m}Tc tracers were applied as yield monitors using ICP-MS and gamma-ray spectrometry respectively. Percent recoveries are reported for a variety of radiochemical separation procedures for water (58-83%), seaweed (10-76%), and for soil matrices (19-79%).

  2. Carboxymethylated polyethylenimine-polymethylenepolyphenylene isocyanate chelating ion exchange resin preconcentration for inductively coupled plasma spectrometry

    SciTech Connect

    Horvath, A.; Barnes, R.M.

    1986-06-01

    A carboxymethylated polyethylenimine-polylmethylenepolyphenylene isocyanate chelating ion exchange resin was prepared, characterized, and used for metals preconcentration for inductively coupled plasma spectrometry. The uptake of copper, cadmium, lead, and zinc by the resin was quantitative in the presence of high concentrations of ammonium, calcium, magnesium, potassium, sodium, and acetate and citrate salts. These metals could be collected from artificial seawater, Dead Sea water, and dissolved bone with a recovery of nearly 100%. The resin also chelates heavy metals and rare earths. Complexed metals can be eluted from the resin column with strong acids. The resin does not change volume with ionic form changes and can be regenerated for repeated use.

  3. Parametric study of compound semiconductor etching utilizing inductively coupled plasma source

    SciTech Connect

    Constantine, C.; Johnson, D.; Barratt, C.

    1996-07-01

    Inductively Coupled Plasma (ICP) sources are extremely promising for large-area, high-ion density etching or deposition processes. In this review the authors compare results for GaAs and GaN etching with both ICP and Electron Cyclotron Resonance (ECR) sources on the same single-wafer platform. The ICP is shown to be capable of very high rates with excellent anisotropy for fabrication of GaAs vias or deep mesas in GaAs or GaN waveguide structures.

  4. Evaluation of Inductively Couple Plasma-time-of-Flight Mass Spectrometry for Laser Ablation Analyses

    SciTech Connect

    S.J. Bajic; D.B. Aeschliman; D.P. Baldwin; R.S. Houk

    2003-09-30

    The purpose of this trip to LECO Corporation was to test the non-matrix matched calibration method and the principal component analysis (PCA) method on a laser ablation-inductively coupled plasma-time of flight mass spectrometry (LA-ICP-TOFMS) system. An LA-ICP-TOFMS system allows for multielement single-shot analysis as well as spatial analysis on small samples, because the TOFMS acquires an entire mass spectrum for all ions extracted simultaneously from the ICP. The TOFMS system differs from the double-focusing mass spectrometer, on which the above methods were developed, by having lower sensitivity and lower mass resolution.

  5. Nanoscale dry etching of germanium by using inductively coupled CF4 plasma

    NASA Astrophysics Data System (ADS)

    Shim, Kyu-Hwan; Yang, Ha Yong; Kil, Yeon-Ho; Yang, Hyeon Deok; Yang, Jong-Han; Hong, Woong-Ki; Kang, Sukill; Jeong, Tae Soo; Kim, Taek Sung

    2012-08-01

    The nanoscale dry etching of germanium was investigated by using inductively coupled CF4 plasma and electron-beam lithography. The optimal dose of PMMA as E-beam lithography resist was ˜200 mC/cm2. When ICP Power was 200W, CF4 gas flow rate was 40 sccm, and process pressure was 20 mTorr, it had a smooth surface and good etch rate. The etching selectivity of Ge wafer to PMMA resist was as low as ˜1.5. Various sub-100 nm dry-etching patterns have been obtained. SEM pictures showed good profile qualities with a smooth etching sidewall and ultrasmall etching features.

  6. Statistical evaluation of an inductively coupled plasma atomic emission spectrometric method for routine water quality testing

    USGS Publications Warehouse

    Garbarino, J.R.; Jones, B.E.; Stein, G.P.

    1985-01-01

    In an interlaboratory test, inductively coupled plasma atomic emission spectrometry (ICP-AES) was compared with flame atomic absorption spectrometry and molecular absorption spectrophotometry for the determination of 17 major and trace elements in 100 filtered natural water samples. No unacceptable biases were detected. The analysis precision of ICP-AES was found to be equal to or better than alternative methods. Known-addition recovery experiments demonstrated that the ICP-AES determinations are accurate to between plus or minus 2 and plus or minus 10 percent; four-fifths of the tests yielded average recoveries of 95-105 percent, with an average relative standard deviation of about 5 percent.

  7. Thomson scattering experiments on a 100 MHz inductively coupled plasma calibrated by Raman scattering

    SciTech Connect

    de Regt, J.M.; Engeln, R.A.H.; de Groote, F.P.J.; van der Mullen, J.A.M.; Schram, D.C.

    1995-05-01

    A new calibration method to obtain the electron density from Thomson scattering on an inductively coupled plasma is discussed. Raman scattering of nitrogen is used for recovering the Rayleigh scattering signal. This has the advantage that no corrections are necessary for stray light, like with other calibration methods, using the direct measured Rayleigh scattering signal on a well-known gas. It is shown that electron densities and electron temperatures can be measured with an accuracy of about 15% in density and of about 150 K in temperature. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  8. Determination of trace metals in marine biological reference materials by inductively coupled plasma mass spectrometry

    SciTech Connect

    Beauchemin, D.; McLaren, J.W.; Willie, S.N.; Berman, S.S.

    1988-04-01

    Inductively coupled plasma mass spectrometry (ICP-MS) was used for the analysis of two marine biological reference materials (dogfish liver tissue (DOLT-1) and dogfish muscle tissue (DORM-1)). The materials were put into solution by digestion in a nitric acid/hydrogen peroxide mixture. Thirteen elements (Na, Mg, Cr, Fe, Mn, Co, Ni, Cu, Zn, As, Cd, Hg, and Pb) were then determined. Accurate results were obtained by standard additions or isotope dilution techniques for all of these elements in DORM-1 and for all but Cr in DOLT-1.

  9. Time-resolved studies of particle effects in laser ablation inductively coupled plasma-mass spectrometry

    SciTech Connect

    Perdian, D.; Bajic, S.; Baldwin, D.; Houk, R.

    2007-11-13

    Time resolved signals in laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) are studied to determine the influence of experimental parameters on ICP-induced fractionation effects. Differences in sample composition and morphology, i.e., ablating brass, glass, or dust pellets, have a profound effect on the time resolved signal. Helium transport gas significantly decreases large positive signal spikes arising from large particles in the ICP. A binder for pellets also reduces the abundance and amplitude of spikes in the signal. MO{sup +} ions also yield signal spikes, but these MO{sup +} spikes generally occur at different times from their atomic ion counterparts.

  10. Production date determination of uranium-oxide materials by inductively coupled plasma mass spectrometry.

    PubMed

    Varga, Zsolt; Surányi, Gergely

    2007-09-01

    The paper describes analytical methods developed for the production date determination of uranium-based nuclear materials by the measurement of 230Th/234U isotope ratio. An improved sample preparation method for the destructive analysis involving extraction chromatographic separation with TEVA resin was applied prior to the measurement by isotope dilution inductively coupled plasma sector field mass spectrometry (ICP-SFMS). The results obtained were compared with the direct, quasi-non-destructive measurement using laser ablation ICP-SFMS technique for age determination. The advantages and limitations of both methods are discussed. PMID:17765059

  11. Characterization of silicon isotropic etch by inductively coupled plasma etcher for microneedle array fabrication

    NASA Astrophysics Data System (ADS)

    Ji, Jing; Tay, Francis E. H.; Miao, Jianmin; Sun, Jianbo

    2006-04-01

    This work investigates the isotropic etching properties in inductively coupled plasma (ICP) etcher for microneedle arrays fabrication. The effects of process variables including powers, gas and pressure on needle structure generation are characterized by factorial design of experiment (DOE). The experimental responses of vertical etching depth, lateral etching length, ratio of vertical etching depth to lateral etching length and photoresist etching rate are reported. The relevance of the etching variables is also presented. The obtained etching behaviours for microneedle structure generation will be applied to develop recipes to fabricate microneedles in designed dimensions.

  12. 15th International Congress on Plasma Physics & 13th Latin American Workshop on Plasma Physics

    NASA Astrophysics Data System (ADS)

    Soto, Leopoldo

    2014-05-01

    The International Advisory Committee of the 15th International Congress on Plasma Physics (ICPP 2010) and the International Advisory Committee of the 13th Latin American Workshop on Plasma Physics (LAWPP 2010), together agreed to carry out this combined meeting ICPP-LAWPP-2010 in Santiago de Chile, 8-13 August 2010, on occasion of the Bicentennial of Chilean Independence. The ICPP-LAWPP-2010 was organized by the Thermonuclear Plasma Department of the Chilean Nuclear Energy Commission (CCHEN) as part of the official program within the framework of the Chilean Bicentennial. The event was also a scientific and academic activity of the project ''Center for Research and Applications in Plasma Physics and Pulsed Power, P4'', supported by National Scientific and Technological Commission, CONICYT-Chile, under grant ACT-26. The International Congress on Plasma Physics was first held in Nagoya, in 1980, and followed by the Congresses: Gothenburg (1982), Lausanne (1984), Kiev (1987), New Delhi (1989), Innsbruck (1992), Foz do Iguacu (1994), Nagoya (1996), Prague (1998), Quebec City (2000), Sydney (2002), Nice (2004), Kiev (2006), and Fukuoka (2008). The purpose of the Congress is to discuss the recent progress and future views in plasma science, including fundamental plasma physics, fusion plasmas, astrophysical plasmas, and plasma applications, and so forth. The Latin American Workshop on Plasma Physics was first held in 1982 in Cambuquira, Brazil, followed by the Workshops: Medellín (1985), Santiago (1988), Buenos Aires (1990), Mexico City (1992), Foz do Iguacu (1994, also combined with ICPP), Caracas (1997), Tandil (1998), La Serena (2000), Sao Pedro (2003), Mexico City (2005), and Caracas (2007). The Latin American Workshop on Plasma Physics is a communication forum of the achievements of the plasma-physics regional community, fostering collaboration between plasma scientists within the region and elsewhere. The program of the ICPP-LAWPP-2010 included the topics

  13. E→H mode transition density and power in two types of inductively coupled plasma configuration

    SciTech Connect

    Wang, Jian; Du, Yin-chang; Zhang, Xiao; Zheng, Zhe; Liu, Yu; Xu, Liang; Wang, Pi; Cao, Jin-xiang

    2014-07-15

    E → H transition power and density were investigated at various argon pressures in inductively coupled plasma (ICP) in a cylindrical interlaid chamber. The transition power versus the pressure shows a minimum transition power at 4 Pa (ν/ω=1) for argon. Then the transition density hardly changes at low pressures (ν/ω≪1), but it increases clearly when argon pressure exceeds an appropriate value. In addition, both the transition power and transition density are lower in the re-entrant configuration of ICP compared with that in the cylindrical configuration of ICP. The result may be caused from the decrease of stochastic heating in the re-entrant configuration of ICP. This work is useful to understand E → H mode transition and control the transition points in real plasma processes.

  14. Low-frequency, self-sustained oscillations in inductively coupled plasmas used for optical pumping

    SciTech Connect

    Coffer, J.; Encalada, N.; Huang, M.; Camparo, J.

    2014-10-28

    We have investigated very low frequency, on the order of one hertz, self-pulsing in alkali-metal inductively-coupled plasmas (i.e., rf-discharge lamps). This self-pulsing has the potential to significantly vary signal-to-noise ratios and (via the ac-Stark shift) resonant frequencies in optically pumped atomic clocks and magnetometers (e.g., the atomic clocks now flying on GPS and Galileo global navigation system satellites). The phenomenon arises from a nonlinear interaction between the atomic physics of radiation trapping and the plasma's electrical nature. To explain the effect, we have developed an evaporation/condensation theory (EC theory) of the self-pulsing phenomenon.

  15. Non-inductive Solenoid-less Plasma Current Start-up in NSTX Using Transient CHI

    SciTech Connect

    Raman, R; Jarboe, T R; Nelson, B A; Bell, M G; Ono, M; Bigelow, T; Kaita, R; LeBlanc, B; Lee, K C; Maqueda, R; Menard, J; Paul, S

    2007-05-23

    Coaxial Helicity Injection (CHI) has been successfully used in the National Spherical Torus Experiment (NSTX) for a demonstration of closed flux current generation without the use of the central solenoid. The favorable properties of the Spherical Torus (ST) arise from its very small aspect ratio. However, small aspect ratio devices have very restricted space for a substantial central solenoid. Thus methods for initiating the plasma current without relying on induction from a central solenoid are essential for the viability of the ST concept. CHI is a promising candidate for solenoid-free plasma startup in a ST. The method has now produced closed flux current up to 160 kA verifying the high current capability of this method in a large ST built with conventional tokamak components.

  16. Sheath-limited unipolar induction in the solar wind. [plasma interactions with solar system bodies

    NASA Technical Reports Server (NTRS)

    Srnka, L. J.

    1975-01-01

    A model of the steady-state interaction between the solar wind and an electrically conducting body having neither an atmosphere nor an intrinsic magnetic field sufficient enough to deflect the plasma flow is presented which considers some effects of a plasma surface sheath on unipolar induction. The Sonett-Colburn (1967, 1968) unipolar dynamo model is reviewed, and it is noted that the unipolar dynamo response of an electrically conducting body in the solar wind's motional field can be controlled by sheath effects in certain cases where the body radius is less than a certain critical value. It is shown that sheath effects do not limit the unipolar response of the moon or Mercury since their body radii are much larger than their critical radii. Sheath effects are also considered for asteroids, the Martian satellites, the irregular Jovian satellites, the outer satellites of Saturn, and meteorite parent bodies in a primordial enhanced solar wind.

  17. Expressing self-absorption in the analytical function of inductively coupled plasma atomic emission spectrometry

    NASA Astrophysics Data System (ADS)

    Kántor, Tibor; Bartha, András

    2015-11-01

    The self-absorption of spectral lines was studied with up to date multi-element inductively coupled plasma atomic emission spectrometry (ICP-AES) instrumentation using radial and axial viewing of the plasma, as well, performing line peak height and line peak area measurements. Two resonance atomic and ionic lines of Cd and Mg were studied, the concentration range was extended up to 2000 mg/L. At the varying analyte concentration, constant matrix concentration of 10,000 mg/L Ca was ensured in the pneumatically nebulized solutions. The physical and the phenomenological formulation of the emission analytical function is overviewed and as the continuity of the earlier results the following equation is offered:

  18. Laser ablation inductively coupled plasma mass spectrometry measurement of isotope ratios in depleted uranium contaminated soils.

    PubMed

    Seltzer, Michael D

    2003-09-01

    Laser ablation of pressed soil pellets was examined as a means of direct sample introduction to enable inductively coupled plasma mass spectrometry (ICP-MS) screening of soils for residual depleted uranium (DU) contamination. Differentiation between depleted uranium, an anthropogenic contaminant, and naturally occurring uranium was accomplished on the basis of measured 235U/238U isotope ratios. The amount of sample preparation required for laser ablation is considerably less than that typically required for aqueous sample introduction. The amount of hazardous laboratory waste generated is diminished accordingly. During the present investigation, 235U/238U isotope ratios measured for field samples were in good agreement with those derived from gamma spectrometry measurements. However, substantial compensation was required to mitigate the effects of impaired pulse counting attributed to sample inhomogeneity and sporadic introduction of uranium analyte into the plasma. PMID:14611049

  19. Fabrication of resonator-quantum well infrared photodetector focal plane array by inductively coupled plasma etching

    NASA Astrophysics Data System (ADS)

    Sun, Jason; Choi, Kwong-Kit

    2016-02-01

    Inductively coupled plasma (ICP) etching has distinct advantages over reactive ion etching in that the etching rates are considerably higher, the uniformity is much better, and the sidewalls of the etched material are highly anisotropic due to the higher plasma density and lower operating pressure. Therefore, ICP etching is a promising process for pattern transfer required during microelectronic and optoelectronic fabrication. Resonator-quantum well infrared photodetectors (R-QWIPs) are the next generation of QWIP detectors that use resonances to increase the quantum efficiency (QE). To fabricate R-QWIP focal plane arrays (FPAs), two optimized ICP etching processes are developed. Using these etching techniques, we have fabricated R-QWIP FPAs of several different formats and pixel sizes with the required dimensions and completely removed the substrates of the FPAs. Their QE spectra were tested to be 30 to 40%. The operability and spectral nonuniformity of the FPA is ˜99.5 and 3%, respectively.

  20. Simulation of low-pressure inductively coupled plasmas: Non-local effects and pulsed power operation

    NASA Astrophysics Data System (ADS)

    Ramamurthi, Badri

    For modeling of low-pressure Inductively Coupled Plasma (ICP) discharges, a number of approaches have been proposed with varying degree of complexity. A self-consistent 1-D model was developed in this work to study the effects of non-local electron conductivity on power absorption and plasma density profiles in a planar inductively coupled argon discharge at low pressures (< 10 mTorr). The self-consistent kinetic description of the discharge included three modules: (1) an EEDF module to compute a non-Maxwellian EEDF, (2) a non-local electron conductivity module which predicted current distribution in the plasma as an integral over the electric field and solved Maxwell's equations to find the self-consistent electric field as well as the non-local power deposition profile and (3) a Heavy Species Transport (HST) module which solved for the ion and metastable atom density and velocity. Results from the full model were then compared with those obtained by using a local conductivity model (Ohm's law) for the RF current. For 10 mTorr, the EEDF was found to be almost Maxwellian with electron temperature ˜ 3 V. As a result, the plasma density profiles obtained from the local and non-local cases were almost identical for the same total power. Interestingly, a similar result was obtained even for a pressure of 1 mTorr where the EEDF was non-Maxwellian. This suggests that as far as species density and flux are concerned, local conductivity models, with lesser computational expense, can be employed even in the non-local regime. Comparisons between simulation and experiment for RF field and current density showed better agreement for non-local model compared with local model. A two-dimensional (r,z) continuum model was then developed to study the spatio-temporal dynamics of a pulsed power (square-wave modulated) discharge in argon (electropositive) and chlorine (electronegative) sustained in an inductively coupled plasma (ICP) reactor with a planar coil. The self

  1. Inductively Coupled Plasma and Electron Cyclotron Resonance Plasma Etching of InGaAlP Compound Semiconductor System

    SciTech Connect

    Abernathy, C.R.; Hobson, W.S.; Hong, J.; Lambers, E.S.; Pearton, S.J.; Shul, R.J.

    1998-11-04

    Current and future generations of sophisticated compound semiconductor devices require the ability for submicron scale patterning. The situation is being complicated since some of the new devices are based on a wider diversity of materials to be etched. Conventional IUE (Reactive Ion Etching) has been prevalent across the industry so far, but has limitations for materials with high bond strengths or multiple elements. IrI this paper, we suggest high density plasmas such as ECR (Electron Cyclotron Resonance) and ICP (Inductively Coupled Plasma), for the etching of ternary compound semiconductors (InGaP, AIInP, AlGaP) which are employed for electronic devices like heterojunction bipolar transistors (HBTs) or high electron mobility transistors (HEMTs), and photonic devices such as light-emitting diodes (LEDs) and lasers. High density plasma sources, opeiating at lower pressure, are expected to meet target goals determined in terms of etch rate, surface morphology, surface stoichiometry, selectivity, etc. The etching mechanisms, which are described in this paper, can also be applied to other III-V (GaAs-based, InP-based) as well as III-Nitride since the InGaAIP system shares many of the same properties.

  2. Inductive Pulsed Plasma Thruster Development and Testing at NASA-MSFC

    NASA Technical Reports Server (NTRS)

    Polzin, Kurt A.

    2013-01-01

    THE inductive pulsed plasma thruster (IPPT) is an electrodeless space propulsion device where a capacitor is charged to an initial voltage and then discharged producing a high current pulse through a coil. The field produced by this pulse ionizes propellant, inductively driving current in a plasma located near the face of the coil. Once the plasma is formed it can be accelerated and expelled at a high exhaust velocity by the electromagnetic Lorentz body force arising from the interaction of the induced plasma current and the magnetic field produced by the current in the coil. In the present work, we present a summary of the IPPT research and development conducted at NASA's Marshall Space Flight Center (MSFC). As a higher-power, still relatively low readiness level system, there are many issues associated with the eventual deployment and use of the IPPT as a primary propulsion system on spacecraft that remain to be addressed. The present program aimed to fabricate and test hardware to explore how these issues could be addressed. The following specific areas were addressed within the program and will be discussed within this paper. a) Conical theta-pinch IPPT geometry thruster configuration. b) Repetition-rate multi-kW thruster pulsing. c) Long-lifetime pulsed gas valve. d) Fast pulsed gas valve driver and controller. e) High-voltage, repetitive capacitor charging power processing unit. During the course of testing, a number of specific tests were conducted, including several that, to our knowledge, have either never been previously conducted (such as multi-KW repetition-rate operation) or have not been performed since the early 1990s (direct IPPT thrust measurements).2 Conical theta-pinch IPPT thrust stand measurements are presented in Fig. 1 while various time-integrated and time

  3. Pulsed Cl2/Ar inductively coupled plasma processing: 0D model versus experiments

    NASA Astrophysics Data System (ADS)

    Despiau-Pujo, E.; Brihoum, M.; Bodart, P.; Darnon, M.; Cunge, G.

    2014-11-01

    Comparisons between measurements and spatially-averaged (0D) simulations of low-pressure Ar and Cl2 pulsed-plasmas in an industrial inductively coupled reactor are reported. Our analysis focuses on the impact of the pulsing parameters (frequency f, duty cycle dc) on the chemical reactivity of the plasma and on the ion fluxes to the walls. Charged particle densities and ion fluxes are highly modulated when the plasma is pulsed at 1 kHz < f < 20 kHz. In rare gas Ar plasmas, the ion flux rise time is short (50 μs), therefore the dc has almost no influence on the ion flux value during the pulse. By contrast, in molecular electronegative Cl2 plasmas, both the value and rise/decay time of the ion flux during the on and off-periods depend strongly on the dc. This is because in Cl2 both the plasma chemistry and electronegativity depend on the dc. During the off-period, the electron density drops much faster than the negative ion density, leading to a large increase in plasma electronegativity. A minimum afterglow time (75 µs) is required for an ion-ion plasma to form and for the sheath to collapse, exposing the walls and wafers to a negative ion flux. The positive ion flux is 3 to 10 times smaller in Cl2 than in Ar for the same operating conditions. In contrast with charged species, the radical (Cl) kinetics are slow and thus the radical density is hardly modulated for f > 1 kHz. However, the dc strongly influences the Cl2/Cl density ratio and is an excellent knob for controlling the plasma chemical reactivity: the higher the dc the higher the Cl density. The trends and quantities in the 0D simulation are in close agreement with experiments. This proves the capacity of global models to reproduce the fundamental features of pulsed plasmas in simple chemistries and to assist the development of pulsed processes.

  4. Core Turbulence and Transport Response to Increasing Toroidal Rotation and Shear in Advanced-Inductive Plasmas

    NASA Astrophysics Data System (ADS)

    McKee, G.; Yan, Z.; Holland, C.; Luce, T.; Petty, C.; Rhodes, T.; Schmitz, L.; Solomon, W.

    2014-10-01

    Multi-scale turbulence properties are altered as core toroidal rotation and ExB shearing rates are systematically varied in relatively high-beta, advanced-inductive H-mode plasmas on DIII-D. The energy confinement time increases by 50% as the toroidal rotation is increased by a factor of 2.5 (to Mo = 0.5), while core turbulence, measured with BES, DBS and PCI, decreases in dimensionlessly matched plasmas (β ~ 2 . 7 ,q95 = 5 . 1). Low-wavenumber (k⊥ρ< 1) density fluctuations obtained with BES near mid-radius exhibit significant amplitude reduction along with a slight reduction in radial correlation length at higher rotation, while fluctuations in the outer region of the plasma, ρ > 0 . 6 , exhibit, but little change in amplitude. Fluctuation measurements and transport behavior will be quantitatively compared with nonlinear simulations. The resulting reduction in confinement will need to be ascertained for low-rotating plasmas such as ITER and FNSF. Work supported by the US DOE under DE-FG02-08ER54999, DE-FG02-07ER54917, DE-FC02-04ER54698, DE-FG02-08ER54984 and DE-AC02-09CH11466.

  5. High sensitivity ultra-broad-band absorption spectroscopy of inductively coupled chlorine plasma

    NASA Astrophysics Data System (ADS)

    Marinov, Daniil; Foucher, Mickaël; Campbell, Ewen; Brouard, Mark; Chabert, Pascal; Booth, Jean-Paul

    2016-06-01

    We propose a method to measure the densities of vibrationally excited Cl2(v) molecules in levels up to v  =  3 in pure chlorine inductively coupled plasmas (ICPs). The absorption continuum of Cl2 in the 250–450 nm spectral range is deconvoluted into the individual components originating from the different vibrational levels of the ground state, using a set of ab initio absorption cross sections. It is shown that gas heating at constant pressure is the major depletion mechanism of the Cl2 feedstock in the plasma. In these line-integrated absorption measurements, the absorption by the hot (and therefore rarefied) Cl2 gas in the reactor centre is masked by the cooler (and therefore denser) Cl2 near the walls. These radial gradients in temperature and density make it difficult to assess the degree of vibrational excitation in the centre of the reactor. The observed line-averaged vibrational distributions, when analyzed taking into account the radial temperature gradient, suggest that vibrational and translational degrees of freedom in the plasma are close to local equilibrium. This can be explained by efficient vibrational-translational (VT) relaxation between Cl2 and Cl atoms. Besides the Cl2(v) absorption band, a weak continuum absorption is observed at shorter wavelengths, and is attributed to photodetachment of Cl‑ negative ions. Thus, line-integrated densities of negative ions in chlorine plasmas can be directly measured using broad-band absorption spectroscopy.

  6. Nanostructure protein repellant amphiphilic copolymer coatings with optimized surface energy by Inductively Excited Low Pressure Plasma.

    PubMed

    Bhatt, Sudhir; Pulpytel, Jérome; Ceccone, Giacomo; Lisboa, Patricia; Rossi, François; Kumar, Virendra; Arefi-Khonsari, Farzaneh

    2011-12-01

    Statistically designed amphiphilic copolymer coatings were deposited onto Thermanox, Si wafer, and quartz crystal microbalance (QCM) substrates via Plasma Enhanced Chemical Vapor Deposition of 1H,1H,2H,2H-perfluorodecyl acrylate and diethylene glycol vinyl ether in an Inductively Excited Low Pressure Plasma reactor. Plasma deposited amphiphilic coatings were characterized by Field Emission Scanning Electron Microscopy, X-ray Photoelectron Spectroscopy, Atomic Force Microscopy, and Water Contact Angle techniques. The surface energy of the coatings can be adjusted between 12 and 70 mJ/m(2). The roughness of the coatings can be tailored depending on the plasma mode used. A very smooth coating was deposited with a CW (continuous wave) power, whereas a rougher surface with R(a) in the range of 2 to 12 nm was deposited with the PW (pulsed wave) mode. The nanometer scale roughness of amphiphilic PFDA-co-DEGVE coatings was found to be in the range of the size of the two proteins namely BSA and lysozyme used to examine for the antifouling properties of the surfaces. The results show that the statistically designed surfaces, presenting a surface energy around 25 mJ/m(2), present no adhesion with respect to both proteins measured by QCM. PMID:22029599

  7. Langmuir Probe Measurements of Inductively Coupled Plasma in CF4/AR/O2 Mixtures

    NASA Technical Reports Server (NTRS)

    Rao, M. V. V. S.; Cruden, Brett; Sharma, Surendra; Meyyappan, Meyya

    2001-01-01

    Inductively coupled plasmas of CF4:Ar:O2, which have been of importance to material processing, were studied in the GEC cell at 80:10:10, 60:20:20, and 40:30:30 mixture ratios. Radial distributions of plasma potential (V(sub p)), electron and ion number densities (n(sub e) and n(sub i)), electron temperature (T(sub e)), and electron energy distribution functions (EEDFs) were measured in the mid-plane of plasma across the electrodes in the pressure range of 10-50 mTorr, and RF power of 200 and 300 W. V(sub p), n(sub e) and n(sub i), which peak in the center of the plasma, increase with decrease of pressure. T(sub e) also increases with pressure but peaks toward the electrode edge. Both V(sub p) and T(sub e) remain nearly independent of RF power, whereas n(sub e) and n(sub i) increase with power. In all conditions the EEDFs exhibit non-Maxwellian shape and are more like Druyvesteyn form at higher energies. They exhibit a broad lip in the energy range 0-10 eV suggesting an electron loss mechanism, which could be due to via resonance electron attachment processes producing negative ions in this rich electronegative gas mixture. This behavior is more prominent towards the electrode edge.

  8. Langmuir Probe Measurements of Inductively Coupled Plasmas in CF4/Ar/O2 Mixtures

    NASA Technical Reports Server (NTRS)

    Rao, M. V. V. S.; Cruden, Brett; Sharma, Surendra; Meyyappan, Meyya

    2001-01-01

    Inductively coupled plasmas of CF4:Ar:O2, which have been of importance to material processing, were studied in the GEC cell at 80:10:10, 60:20:20, and 40:30:30 mixture ratios. Radial distributions of plasma potential (V(sub p)), electron and ion number densities (n(sub e) and n(sub i), electron temperature (T(sub e)), and electron energy distribution functions (EEDFs) were measured in the mid-plane of plasma across the electrodes in the pressure range of 10-50 mTorr, and RF (radio frequency) power of 200 and 300 W. V(sub p), n(sub e) and n(sub i), which peak in the center of the plasma, increase with decrease of pressure. T(sub e) also increases with pressure but peaks toward the electrode edge. Both V(sub p) and T(sub e) remain nearly independent of RF power, whereas n(sub e) and n(sub i) increase with power. In all conditions the EEDFs exhibit non-Maxwellian shape and are more like Druyvesteyn form at higher energies. They exhibit a broad dip in the energy range 0-10 eV suggesting an electron loss mechanism, which could be due to via resonance electron attachment processes producing negative ions in this rich electronegative gas mixture. This behavior is more prominent towards the electrode edge.

  9. High Resolution Studies of the Origins of Polyatomic Ions in Inductively Coupled Plasma-Mass Spectrometry

    SciTech Connect

    Jill Wisnewski Ferguson

    2006-08-09

    The inductively coupled plasma (ICP) is an atmospheric pressure ionization source. Traditionally, the plasma is sampled via a sampler cone. A supersonic jet develops behind the sampler, and this region is pumped down to a pressure of approximately one Torr. A skimmer cone is located inside this zone of silence to transmit ions into the mass spectrometer. The position of the sampler and skimmer cones relative to the initial radiation and normal analytical zones of the plasma is key to optimizing the useful analytical signal [1]. The ICP both atomizes and ionizes the sample. Polyatomic ions form through ion-molecule interactions either in the ICP or during ion extraction [l]. Common polyatomic ions that inhibit analysis include metal oxides (MO{sup +}), adducts with argon, the gas most commonly used to make up the plasma, and hydride species. While high resolution devices can separate many analytes from common interferences, this is done at great cost in ion transmission efficiency--a loss of 99% when using high versus low resolution on the same instrument [2]. Simple quadrupole devices, which make up the bulk of ICP-MS instruments in existence, do not present this option. Therefore, if the source of polyatomic interferences can be determined and then manipulated, this could potentially improve the figures of merit on all ICP-MS devices, not just the high resolution devices often utilized to study polyatomic interferences.

  10. An inductively coupled plasma source for the Gaseous Electronics Conference RF Reference Cell

    SciTech Connect

    Miller, P.A.; Hebner, G.A.; Greenberg, K.E.; Pochan, P.D.; Aragon, B.P.

    1995-07-01

    In order to extend the operating range of the GEC RF Reference Cell, the authors developed an inductively coupled plasma source that replaced the standard parallel-plate upper-electrode assembly. Voltage and current probes, Langmuir probes, and an 80 GHz interferometer provided information on plasmas formed in argon, chlorine, and nitrogen at pressures from 0.1 Pa to 3 Pa. For powers deposited in the plasma from 20 W to 300 W, the source produced peak electron densities between 10{sup 10}/cm{sup 3} and 10{sup 12}/cm{sup 3} and electron temperatures near 4 eV. The electron density peaked on axis with typical full-width at half maximum of 7 cm to 9 cm. Discharges in chlorine and nitrogen had bimodal operation that was clearly evident from optical emission intensity. A dim mode occurred at low power and a bright mode at high power. The transition between modes had hysteresis. After many hours of high-power operation, films formed on electrodes and walls of one Cell. These deposits affected the dim-to-bright mode transition, and also apparently caused generation of hot electrons and increased the plasma potential.

  11. Mode transition in CF{sub 4} + Ar inductively coupled plasma

    SciTech Connect

    Liu, Wei; Gao, Fei; Zhao, Shu-Xia; Li, Xue-Chun; Wang, You-Nian

    2013-12-15

    The E to H mode transitions are studied by a hairpin probe and optical emission spectroscopy in inductively coupled CF{sub 4} + Ar plasmas. Electron density, optical emission intensity of Ar, and the voltage and current are measured during the E to H mode transitions. It is found that the electron density and plasma emission intensity increase continuously at low pressure during the E to H mode transition, while they jump up discontinuously at high pressure. Meanwhile, the transition threshold power and △P (the power interval between E and H mode) increase by increasing the pressure. When the ratio of CF{sub 4} increases, the E to H mode transition happens at higher applied power, and meanwhile, the △P also significantly increases. Besides, the effects of CF{sub 4} gas ratio on the plasma properties and the circuit electrical properties in both pure E and H modes were also investigated. The electron density and plasma emission intensity both decrease upon increasing the ratio of CF{sub 4} at the two modes, due to the stronger electrons loss scheme. The applied voltages at E and H modes both increase as increasing the CF{sub 4} gas ratio, however the applied current at two modes behave just oppositely with the gas ratio.

  12. Effect of an Additional, Parallel Capacitor on Pulsed Inductive Plasma Accelerator Performance

    NASA Technical Reports Server (NTRS)

    Polzin, Kurt A.; Sivak, Amy D.; Balla, Joseph V.

    2011-01-01

    A model of pulsed inductive plasma thrusters consisting of a set of coupled circuit equations and a one-dimensional momentum equation has been used to study the effects of adding a second, parallel capacitor into the system. The equations were nondimensionalized, permitting the recovery of several already-known scaling parameters and leading to the identification of a parameter that is unique to the particular topology studied. The current rise rate through the inductive acceleration coil was used as a proxy measurement of the effectiveness of inductive propellant ionization since higher rise rates produce stronger, potentially better ionizing electric fields at the coil face. Contour plots representing thruster performance (exhaust velocity and efficiency) and current rise rate in the coil were generated numerically as a function of the scaling parameters. The analysis reveals that when the value of the second capacitor is much less than the first capacitor, the performance of the two-capacitor system approaches that of the single-capacitor system. In addition, as the second capacitor is decreased in value the current rise rate can grow to be twice as great as the rise rate attained in the single capacitor case.

  13. Viscous effects on motion and heating of electrons in inductively coupled plasma reactors

    SciTech Connect

    Chang, C.H.; Bose, D.

    1999-10-01

    A transport model is developed for nonlocal effects on motion and heating of electrons in inductively coupled plasma reactors. The model is based on the electron momentum equation derived from the Boltzmann equation, retaining anisotropic stress components which in fact are viscous stresses. The resulting model consists of transport equations for the magnitude of electron velocity oscillation and terms representing energy dissipation due to viscous stresses in the electron energy equation. In this model, electrical current is obtained in a nonlocal manner due to viscous effects, instead of Ohm's law or the electron momentum equation without viscous effects, while nonlocal heating of electrons is represented by the viscous dissipation. Computational results obtained by two-dimensional numerical simulations show that nonlocal determination of electrical current indeed is important, and viscous dissipation becomes an important electron heating mechanism at low pressures. It is suspected that viscous dissipation in inductively coupled plasma reactors in fact represents stochastic heating of electrons, and this possibility is exploited by discussing physical similarities between stochastic heating and energy dissipation due to the stress tensor.

  14. Langmuir Probe and Mass Spectroscopic Measurements in Inductively Coupled CF4 Plasmas

    NASA Technical Reports Server (NTRS)

    Rao, M. V. V. S.; Sharma, Surendra; Cruden, B. A.; Meyyappan, M.

    2001-01-01

    Abstract Electron and ion energy distribution functions and other plasma parameters such as plasma potential (V(sub p)) , electron temperature (T(sub e)), and electron and ion number densities (n (sub e) and n(sub i)) in low pressure CF4 plasmas have been measured. The experiments were conducted in a GEC cell using an inductively coupled plasma (ICP) device powered by a 13.56 MHz radio-frequency (rf) power source. The measurements were made at 300 W of input rf power at 10, 30 and 50 mTorr gas pressures. Langmuir probe measurements suggest that n(sub e), n(sub i) and V(sub p) remain constant over 60% of the central electrode area, beyond which they decrease. Within the limits of experimental error (+/- 0.25 eV), T(sub e) remains nearly constant over the electrode area. T(sub e) and V(sub p) increase with a decrease in pressure. n(sub e) and n(sub i) are not affected as significantly as T(sub e) or V(sub p) by variation in the gas pressure. The electron energy distribution function (EEDF) measurements indicate a highly non-Maxwellian plasma. CF3+ is the most dominant ion product of the plasma, followed by CF2+ and CF+. The concentrations of CF2+ and CF+ are much larger than that is possible from direct electron impact ionization of the parent gas. The cross-section data suggest that the direct electron impact ionization of fragment neutrals and negative ion production by electron attachment may be responsible for increase of the minor ions.

  15. A 5 kA pulsed power supply for inductive and plasma loads in large volume plasma device

    NASA Astrophysics Data System (ADS)

    Srivastava, P. K.; Singh, S. K.; Sanyasi, A. K.; Awasthi, L. M.; Mattoo, S. K.

    2016-07-01

    This paper describes 5 kA, 12 ms pulsed power supply for inductive load of Electron Energy Filter (EEF) in large volume plasma device. The power supply is based upon the principle of rapid sourcing of energy from the capacitor bank (2.8 F/200 V) by using a static switch, comprising of ten Insulated Gate Bipolar Transistors (IGBTs). A suitable mechanism is developed to ensure equal sharing of current and uniform power distribution during the operation of these IGBTs. Safe commutation of power to the EEF is ensured by the proper optimization of its components and by the introduction of over voltage protection (>6 kV) using an indigenously designed snubber circuit. Various time sequences relevant to different actions of power supply, viz., pulse width control and repetition rate, are realized through optically isolated computer controlled interface.

  16. A 5 kA pulsed power supply for inductive and plasma loads in large volume plasma device.

    PubMed

    Srivastava, P K; Singh, S K; Sanyasi, A K; Awasthi, L M; Mattoo, S K

    2016-07-01

    This paper describes 5 kA, 12 ms pulsed power supply for inductive load of Electron Energy Filter (EEF) in large volume plasma device. The power supply is based upon the principle of rapid sourcing of energy from the capacitor bank (2.8 F/200 V) by using a static switch, comprising of ten Insulated Gate Bipolar Transistors (IGBTs). A suitable mechanism is developed to ensure equal sharing of current and uniform power distribution during the operation of these IGBTs. Safe commutation of power to the EEF is ensured by the proper optimization of its components and by the introduction of over voltage protection (>6 kV) using an indigenously designed snubber circuit. Various time sequences relevant to different actions of power supply, viz., pulse width control and repetition rate, are realized through optically isolated computer controlled interface. PMID:27475553

  17. Internal Model Controller of an ANN Speed Sensorless Controlled Induction Motor Drives

    NASA Astrophysics Data System (ADS)

    Hamed Mouna, Ben; Lassaad, Sbita

    This study deals with the performance analysis and implementation of a robust sensorless speed controller. The robustness is guaranteed by the use of the Internal Model Controller (IMC). An intelligent algorithm is evolved to eliminate the mechanical speed. It is based on the Artificial Neural Network (ANN) principle. Verification of the proposed robust sensorless controller is provided by experimental realistic tests on a scalar controlled induction motor drive. Sensorless robust speed control at low speeds and in field weakening region (high speeds) is studied in order to show the robustness of the speed controller under a wide range of load.

  18. [Determination of Cr, Ni, Cu, Mn, P, Si, Mo and Ti in high chromium cast iron by inductively coupled plasma atomic emission spectrometry].

    PubMed

    Wang, Hui; Wang, Guo-Xin; Xu, Yu-Yu; Yu, Lu; Yang, Peng-Yuan

    2011-09-01

    The high-chromium cast iron sample was microwave-assisted digested with aqueous regia in a closed vessel. Series standards were prepared with matching Fe matrix and adding Y as internal standard. Line intensities of the prepared standards and the digested sample solutions were determined by inductively coupled plasma atomic emission spectrometry. Accuracy of the proposed method was verified by the analysis of three national standard Materials GSBH 41018, GBW 01120 and GBW 01121, and the results were well agreed with the certification data. PMID:22097871

  19. High precision and high accuracy isotopic measurement of uranium using lead and thorium calibration solutions by inductively coupled plasma-multiple collector-mass spectrometry

    SciTech Connect

    Bowen, I.; Walder, A.J.; Hodgson, T.; Parrish, R.R. |

    1998-12-31

    A novel method for the high accuracy and high precision measurement of uranium isotopic composition by Inductively Coupled Plasma-Multiple Collector-Mass Spectrometry is discussed. Uranium isotopic samples are spiked with either thorium or lead for use as internal calibration reference materials. This method eliminates the necessity to periodically measure uranium standards to correct for changing mass bias when samples are measured over long time periods. This technique has generated among the highest levels of analytical precision on both the major and minor isotopes of uranium. Sample throughput has also been demonstrated to exceed Thermal Ionization Mass Spectrometry by a factor of four to five.

  20. Complex image method for RF antenna-plasma inductive coupling calculation in planar geometry. Part II: measurements on a resonant network

    NASA Astrophysics Data System (ADS)

    Guittienne, Ph; Jacquier, R.; Howling, A. A.; Furno, I.

    2015-12-01

    Measurements and analysis of a radio-frequency planar antenna are presented for applications in inductively-coupled plasma processing. The network of inductive and capacitive elements exhibits high currents under resonance which are efficient for plasma generation. Mode frequencies and impedances are accurately calculated by accounting for the mutual partial inductances using the impedance matrix. The effect of plasma inductive coupling on mode frequency shift and mode impedance is estimated using the complex image method, giving good agreement with experiment. It is proposed that the complex image method combined with the partial inductance concept (see the accompanying paper, Part I (Howling et al 2015 Plasma Sources Sci. Technol. 24 065014)) offers a general way to calculate the impedance characteristics of inductively-coupled plasma sources in planar geometry.

  1. Determination of trace rare earth elements in gadolinium aluminate by inductively coupled plasma time of flight mass spectrometry

    NASA Astrophysics Data System (ADS)

    Saha, Abhijit; Deb, S. B.; Nagar, B. K.; Saxena, M. K.

    An analytical methodology was developed for the precise quantification of ten trace rare earth elements (REEs), namely, La, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, and Tm, in gadolinium aluminate (GdAlO3) employing an ultrasonic nebulizer (USN)-desolvating device based inductively coupled plasma mass spectrometry (ICP-MS). A microwave digestion procedure was optimized for digesting 100 mg of the refractory oxide using a mixture of sulphuric acid (H2SO4), phosphoric acid (H3PO4) and water (H2O) with 1400 W power, 10 min ramp and 60 min hold time. An USN-desolvating sample introduction system was employed to enhance analyte sensitivities by minimizing their oxide ion formation in the plasma. Studies on the effect of various matrix concentrations on the analyte intensities revealed that precise quantification of the analytes was possible with matrix level of 250 mg L- 1. The possibility of using indium as an internal standard was explored and applied to correct for matrix effect and variation in analyte sensitivity under plasma operating conditions. Individual oxide ion formation yields were determined in matrix matched solution and employed for correcting polyatomic interferences of light REE (LREE) oxide ions on the intensities of middle and heavy rare earth elements (MREEs and HREEs). Recoveries of ≥ 90% were achieved for the analytes employing standard addition technique. Three real samples were analyzed for traces of REEs by the proposed method and cross validated for Eu and Nd by isotope dilution mass spectrometry (IDMS). The results show no significant difference in the values at 95% confidence level. The expanded uncertainty (coverage factor 1σ) in the determination of trace REEs in the samples were found to be between 3 and 8%. The instrument detection limits (IDLs) and the method detection limits (MDLs) for the ten REEs lie in the ranges 1-5 ng L- 1 and 7-64 μg kg- 1 respectively.

  2. Experimental measurement of plasma parameters and electron energy distribution in ferrite-core side type Ar/He inductively coupled plasma

    NASA Astrophysics Data System (ADS)

    Han, Duksun; Bang, Jin-Young; Lee, Hyo-Chang; Chung, Chin-Wook

    2012-10-01

    Spatial distributions of a plasma density and an effective electron temperature (Teff) were studied from the measurement of an electron energy probability function (EEPF) in the side type ferrite-core inductively coupled plasma with an argon-helium mixture. As the helium gas was diluted at the fixed total gas pressure of 5 mTorr in an argon discharge, the distribution of the plasma density was changed from a concave to a flat, and finally became a convex, while all spatial profiles of Teff were the hollow shapes with the helium dilution. This evolution of the plasma uniformity with the helium gas could be explained by the increased energy relaxation length and the changed plasma potential, indicating the transition of the electron kinetics from the local to non-local kinetics. From this result, it is expected that the addition of helium gas could be applied as a method to control the plasma uniformity in a large area plasma processing.

  3. Induction Plasma Sprayed Nano Hydroxyapatite Coatings on Titanium for Orthopaedic and Dental Implants

    PubMed Central

    Roy, Mangal; Bandyopadhyay, Amit; Bose, Susmita

    2011-01-01

    This paper reports preparation of a highly crystalline nano hydroxyapatite (HA) coating on commercially pure titanium (Cp-Ti) using inductively coupled radio frequency (RF) plasma spray and their in vitro and in vivo biological response. HA coatings were prepared on Ti using normal and supersonic plasma nozzles at different plate powers and working distances. X-ray diffraction (XRD) and Fourier transformed infrared spectroscopic (FTIR) analysis show that the normal plasma nozzle lead to increased phase decomposition, high amorphous calcium phosphate (ACP) phase formation, and severe dehydroxylation of HA. In contrast, coatings prepared using supersonic nozzle retained the crystallinity and phase purity of HA due to relatively short exposure time of HA particles in the plasma. In addition, these coatings exhibited a microstructure that varied from porous and glassy structure at the coating-substrate interface to dense HA at the top surface. The microstructural analysis showed that the coating was made of multigrain HA particles of ~200 nm in size, which consisted of recrystallized HA grains in the size range of 15– 20 nm. Apart from the type of nozzle, working distance was also found to have a strong influence on the HA phase decomposition, while plate power had little influence. Depending on the plasma processing conditions, a coating thickness between 300 and 400 μm was achieved where the adhesive bond strengths were found to be between 4.8 MPa to 24 MPa. The cytotoxicity of HA coatings was examined by culturing human fetal osteoblast cells (hFOB) on coated surfaces. In vivo studies, using the cortical defect model in rat femur, evaluated the histological response of the HA coatings prepared with supersonic nozzle. After 2 weeks of implantation, osteoid formation was evident on the HA coated implant surface, which could indicate early implant- tissue integration in vivo. PMID:21552358

  4. Comparisons of Two Plasma Instruments on the International Space Station

    NASA Astrophysics Data System (ADS)

    Balthazor, R.; McHarg, M. G.; Minow, J. I.; Chandler, M. O.; Musick, J. D.; Feldmesser, H.; Darrin, M. A.; Osiander, R.

    2011-12-01

    The United States Air Force Academy's Canary instrument, a low-cost ion spectrometer with integrated charge multiplication, was installed on the International Space Station (ISS) on shuttle flight STS-134. The primary goal of the Canary experiment is to measure ion signals in the wake when ISS is flying in the standard +XVV attitude. However, the instrument is pointed (approximately) into ram and detects ambient Low Earth Orbit ions when the ISS is flying in the -XVV attitude. Simultaneous observations with NASA's Floating Plasma Measurement Unit (FPMU) have been taken during these times, and the results from each instrument are compared, in order to determine the origin of energy variations observed in the Canary ion signal. In addition, insights into the ISS floating plasma potential at the two different instrument locations can be obtained.

  5. Improvement of the capabilities of inductively coupled plasma optical emission spectrometry by replacing the desolvation system of an ultrasonic nebulization system with a pre-evaporation tube

    NASA Astrophysics Data System (ADS)

    Asfaw, Alemayehu; Beauchemin, Diane

    2010-05-01

    The effect of replacing the desolvation system (i.e., heater/condenser (HC) and membrane desolvator (MD)) of an ultrasonic nebulizer (USN) system with a pre-evaporation tube (PET) that is heated to about 400 °C on the analytical capabilities of inductively coupled plasma optical emission spectrometry (ICP-OES) was investigated. A multivariate optimisation was conducted in each case to find operating conditions maximizing plasma robustness. Under optimum conditions, the analytical performance of ICP-OES was significantly improved (i.e., better sensitivity, detection limit and plasma robustness) with USN-PET compared to that achieved with both the commercially-available USN-HC-MD and a conventional pneumatic nebulizer/spray chamber sample introduction system. However, only the USN-PET approach allows the determination of Hg, which appears to otherwise be lost in the heater/condenser system. Using a simple external calibration, without any matrix matching, and using an argon emission line for internal standardization, the results obtained for the determination of trace elements in certified soil reference materials (SRM 2710 and 2711) by USN-PET were in good agreement with certified values. This is unlike with conventional sample introduction systems where internal standardization using an Ar line is unusual, as it does not compensate for physical interferences, and either internal standardization (with internal standards added to the sample and standard solutions) or matrix-matched calibration is required.

  6. Spatial and temporal evolution of negative ions in a pulsed inductively coupled hydrogen plasma source across a magnetic filter

    NASA Astrophysics Data System (ADS)

    Nulty, Stuart; Corr, Cormac

    2015-09-01

    Low-temperature electronegative plasmas have important applications in high-energy sources for fusion energy, plasma thrusters and materials processing. Neutral beam injection systems and space thruster technology such as the PEGASUS propulsion system rely on efficiently producing extractable negative ions. In this work we investigate the production of hydrogen negative ions in a pulsed inductively coupled plasma across a magnetic filter. The electron energy distribution function, plasma density and electron temperature are determined using an RF compensated Langmuir probe, and time-resolved laser photo-detachment is used to measure the negative ion fraction. The spatial and temporal evolution of these plasma parameters within the plasma source will be presented. Using a pulsed plasma and a magnetic filter, the electron temperature can be efficiently controlled and a higher density of negative ions compared to electrons can be obtained at certain locations within the source.

  7. Numerical simulations of tokamak plasma turbulence and internal transport barriers

    NASA Astrophysics Data System (ADS)

    Thyagaraja, A.

    2000-12-01

    A wide variety of magnetically confined plasmas, including many tokamaks such as the JET, TFTR, JT-60U, DIII-D, RTP, show clear evidence for the existence of the so-called `internal transport barriers' (ITBs) which are regions of relatively good confinement, associated with substantial gradients in temperature and/or density. A computational approach to investigating the properties of tokamak plasma turbulence and transport is developed. This approach is based on the evolution of global, two-fluid, nonlinear, electromagnetic plasma equations of motion with specified sources. In this paper, the computational model is applied to the problem of determining the nature and physical characteristics of barrier phenomena, with particular reference to RTP (electron-cyclotron resonance heated) and JET (neutral beam heated) observations of ITBs. The simulations capture features associated with the formation of these ITBs, and qualitatively reproduce some of the observations made on RTP and JET. The picture of plasma turbulence suggested involves variations of temperature and density profiles induced by the electromagnetic fluctuations, on length scales intermediate between the system size and the ion Larmor radius, and time scales intermediate between the confinement time and the Alfvén time (collectively termed `mesoscales'). The back-reaction of such profile `corrugations' (features exhibiting relatively high local spatial gradients and rapid time variations) on the development and saturation of the turbulence itself plays a key role in the nonlinear dynamics of the system. The corrugations are found to modify the dynamical evolution of radial electric field shear and the bootstrap current density, which in turn influence the turbulence. The interaction is mediated by relatively long wavelength, electromagnetic modes excited by an inverse cascade and involving nonlinear instabilities and relaxation phenomena such as intermittency and internal mode locking.

  8. Characterization of electron kinetics regime with electron energy probability functions in inductively coupled hydrogen plasmas

    NASA Astrophysics Data System (ADS)

    Kim, June Young; Cho, Won-Hwi; Dang, Jeong-Jeung; Chung, Kyoung-Jae; Hwang, Y. S.

    2016-02-01

    Electron kinetics regime is characterized with the evolution of electron energy probability functions (EEPFs) in inductively coupled hydrogen plasmas. Measurements on EEPFs are carried out with a radio-frequency-compensated single Langmuir probe at the center of a planar-type hydrogen plasma driven by 13.56 MHz wave frequency. Measured EEPFs deviate considerably from the Maxwellian distribution only at relatively high pressures (15-40 mTorr), and the effective electron temperature steeply decreases as the gas pressure increases. Such evolution of the EEPF shapes with pressures is discussed in the consideration of the electron energy relaxation length and various characteristic frequencies. It is found that the EEPFs show locally depleted electron energy distribution where the electron-molecule vibrational collision frequency exceeds the electron-electron collision frequency at the local kinetics regime, while the measured EEPF is not dependent on the vibrational collision frequency at the non-local kinetics regime. Variation of the EEPF shape with distance from the heating region at the local kinetics regime is also well explained in the context of the energy relaxation length and electron-molecule collision frequencies. This study indicates that the control of electron energy distribution should be carried out in the consideration of electron kinetic regime depending on the energy relaxation length for various hydrogen plasma sources.

  9. Surface roughening of ground fused silica processed by atmospheric inductively coupled plasma

    NASA Astrophysics Data System (ADS)

    Xin, Qiang; Li, Na; Wang, Jun; Wang, Bo; Li, Guo; Ding, Fei; Jin, Huiliang

    2015-06-01

    Subsurface damage (SSD) is a defect that is inevitably induced during mechanical processes, such as grinding and polishing. This defect dramatically reduces the mechanical strength and the laser damage thresholds of optical elements. Compared with traditional mechanical machining, atmospheric pressure plasma processing (APPP) is a relatively novel technology that induces almost no SSD during the processing of silica-based optical materials. In this paper, a form of APPP, inductively coupled plasma (ICP), is used to process fused silica substrates with fluorocarbon precursor under atmospheric pressure. The surface morphology evolution of ICP-processed substrates was observed and characterized by confocal laser scanning microscope (CLSM), field emission scanning electron microscope (SEM), and atomic force microscopy (AFM). The results show that the roughness evolves with the etching depth, and the roughness evolution is a single-peaked curve. This curve results from the opening and the coalescing of surface cracks and fractures. The coalescence procedure of these microstructures was simulated with two common etched pits on a polished fused silica surface. Understanding the roughness evolution of plasma-processed surface might be helpful in optimizing the optical fabrication chain that contains APPP.

  10. Measuring ion velocity distribution functions through high-aspect ratio holes in inductively coupled plasmas

    NASA Astrophysics Data System (ADS)

    Cunge, G.; Darnon, M.; Dubois, J.; Bezard, P.; Mourey, O.; Petit-Etienne, C.; Vallier, L.; Despiau-Pujo, E.; Sadeghi, N.

    2016-02-01

    Several issues associated with plasma etching of high aspect ratio structures originate from the ions' bombardment of the sidewalls of the feature. The off normal angle incident ions are primarily due to their temperature at the sheath edge and possibly to charging effects. We have measured the ion velocity distribution function (IVDF) at the wafer surface in an industrial inductively coupled plasma reactor by using multigrid retarding field analyzers (RFA) in front of which we place 400 μm thick capillary plates with holes of 25, 50, and 100 μm diameters. The RFA then probes IVDF at the exit of the holes with Aspect Ratios (AR) of 16, 8, and 4, respectively. The results show that the ion flux dramatically drops with the increase in AR. By comparing the measured IVDF with an analytical model, we concluded that the ion temperature is 0.27 eV in our plasma conditions. The charging effects are also observed and are shown to significantly reduce the ion energy at the bottom of the feature but only with a "minor" effect on the ion flux and the shape of the IVDF.

  11. Measurements of collisionless heating effects in the H-mode of an inductively coupled plasma system

    NASA Astrophysics Data System (ADS)

    Zaka-Ul-Islam, Mujahid; Graham, Bill; Gans, Timo; Niemi, Kari; O'Connell, Deborah

    2013-09-01

    Inductively coupled plasma systems (ICPs) for processing applications are often operated at low pressures, in the near-collisionless regime. In this regime, the electron mean free path is comparable or larger than the plasma dimensions. The electron dynamics in such ICPs has been investigated here, using phase and space resolved optical emission spectroscopy (PROES) and Langmuir probe measurements. The PROES measurements are also used to calculate the Fourier harmonics components of the 2D excitation (in the radial axial plane). The experimental system is a standard GEC cell with the axial gap of ~4 cm, powered by 13.56 MHz RF power supply. The gas pressure was varied between 0.5 - 2 Pa. The PROES measurements and Fourier harmonics components confirm many of the previous simulation results in comparable operational regimes. The results show that in the 2D (radial-axial) plane, the plasma power is deposited in a spatially non-uniform and non-linear manner, with axial layers of positive and negative power absorption. The contribution of these nonlinear effects decreases with an increase in the pressure, as observed in previous experimental and simulation results.

  12. Effect of low-damage inductively coupled plasma on shallow nitrogen-vacancy centers in diamond

    SciTech Connect

    Fávaro de Oliveira, Felipe; Momenzadeh, S. Ali; Wang, Ya; Denisenko, Andrej; Konuma, Mitsuharu; Markham, Matthew; Edmonds, Andrew M.; Wrachtrup, Jörg

    2015-08-17

    Near-surface nitrogen-vacancy (NV) centers in diamond have been successfully employed as atomic-sized magnetic field sensors for external spins over the last years. A key challenge is still to develop a method to bring NV centers at nanometer proximity to the diamond surface while preserving their optical and spin properties. To that aim we present a method of controlled diamond etching with nanometric precision using an oxygen inductively coupled plasma process. Importantly, no traces of plasma-induced damages to the etched surface could be detected by X-ray photoelectron spectroscopy and confocal photoluminescence microscopy techniques. In addition, by profiling the depth of NV centers created by 5.0 keV of nitrogen implantation energy, no plasma-induced quenching in their fluorescence could be observed. Moreover, the developed etching process allowed even the channeling tail in their depth distribution to be resolved. Furthermore, treating a {sup 12}C isotopically purified diamond revealed a threefold increase in T{sub 2} times for NV centers with <4 nm of depth (measured by nuclear magnetic resonance signal from protons at the diamond surface) in comparison to the initial oxygen-terminated surface.

  13. Effect of low-damage inductively coupled plasma on shallow nitrogen-vacancy centers in diamond

    NASA Astrophysics Data System (ADS)

    Fávaro de Oliveira, Felipe; Momenzadeh, S. Ali; Wang, Ya; Konuma, Mitsuharu; Markham, Matthew; Edmonds, Andrew M.; Denisenko, Andrej; Wrachtrup, Jörg

    2015-08-01

    Near-surface nitrogen-vacancy (NV) centers in diamond have been successfully employed as atomic-sized magnetic field sensors for external spins over the last years. A key challenge is still to develop a method to bring NV centers at nanometer proximity to the diamond surface while preserving their optical and spin properties. To that aim we present a method of controlled diamond etching with nanometric precision using an oxygen inductively coupled plasma process. Importantly, no traces of plasma-induced damages to the etched surface could be detected by X-ray photoelectron spectroscopy and confocal photoluminescence microscopy techniques. In addition, by profiling the depth of NV centers created by 5.0 keV of nitrogen implantation energy, no plasma-induced quenching in their fluorescence could be observed. Moreover, the developed etching process allowed even the channeling tail in their depth distribution to be resolved. Furthermore, treating a 12C isotopically purified diamond revealed a threefold increase in T2 times for NV centers with <4 nm of depth (measured by nuclear magnetic resonance signal from protons at the diamond surface) in comparison to the initial oxygen-terminated surface.

  14. Vibrational kinetics in Cl2 and O2 low-pressure inductively-coupled plasmas

    NASA Astrophysics Data System (ADS)

    Booth, Jean-Paul; Foucher, Mickael; Marinov, Daniil; Chabert, Pascal; Annusova, Anna; Guerra, Vasco; Agarwal, Ankur; Rauf, Shahid

    2015-09-01

    Low energy electron interactions with molecules via resonances can cause vibrational excitation (affecting chemical kinetics), electron energy loss and modification of the EEDF. However, with the exception of N2 and H2 plasmas, very little attention has been paid to this subject. We have implemented a novel high-sensitivity ultra-broadband UV absorption bench, allowing spectra to be recorded with noise as low as 2×10-5 over a 250 nm wavelength range, and recording of complete vibronic bands. We applied this to radiofrequency inductively-coupled plasmas in low pressure (5-50 mTorr) pure O2 and pure Cl2. In O2 plasmas we surprisingly observe highly vibrationally excited O2 (v'' up to 18) via B-X Schumann-Runge bands. Cl2 molecules show a broad UV absorption spectrum in the region 250-400 nm, with distinctly different absorption spectra for vibrationally excited molecules. However, only a small fraction of the Cl2 molecules were observed in vibrationally excited states and the vibrational temperature is close to equilibrium with the local gas translational temperature (up to 1000 K), in contrast to O2. We are currently working on global models with vibrational kinetics to explain these results. Work supported by LABEX Plas@par (ANR-11-IDEX-0004-02), and Applied Materials.

  15. Optimization of operating parameters for inductively coupled plasma mass spectrometry: A computational study

    NASA Astrophysics Data System (ADS)

    Aghaei, Maryam; Lindner, Helmut; Bogaerts, Annemie

    2012-10-01

    An inductively coupled plasma, connected to a mass spectrometer interface, is computationally investigated. The effect of pressure behind the sampler, injector gas flow rate, auxiliary gas flow rate, and applied power is studied. There seems to be an optimum range of injector gas flow rate for each setup which guaranties the presence and also a proper length of the central channel in the torch. Moreover, our modeling results show that for any specific purpose, it is possible to control that either only the central gas flow passes through the sampler orifice or that it is accompanied by the auxiliary gas flow. It was also found that depending on geometry, the variation of outgoing gas flow rate is much less than the variation of the injector gas flow rate and this causes a slightly higher pressure inside the torch. The general effect of increasing the applied power is a rise in the plasma temperature, which results in a higher ionization in the coil region. However, the negative effect is reducing the length of the cool central channel which is important to transfer the sample substances to the sampler. Using a proper applied power can enhance the efficiency of the system. Indeed, by changing the gas path lines, the power can control which flow (i.e., only from injector gas or also from the auxiliary gas) goes to the sampler orifice. Finally, as also reported from experiments in literature, the pressure behind the sampler has no dramatic effect on the plasma characteristics.

  16. Fundamental studies of the plasma extraction and ion beam formation processes in inductively coupled plasma mass spectrometry

    SciTech Connect

    Niu, Hongsen

    1995-02-10

    The fundamental and practical aspects are described for extracting ions from atmospheric pressure plasma sources into an analytical mass spectrometer. Methodologies and basic concepts of inductively coupled plasma mass spectrometry (ICP-MS) are emphasized in the discussion, including ion source, sampling interface, supersonic expansion, slumming process, ion optics and beam focusing, and vacuum considerations. Some new developments and innovative designs are introduced. The plasma extraction process in ICP-MS was investigated by Langmuir measurements in the region between the skimmer and first ion lens. Electron temperature (T{sub e}) is in the range 2000--11000 K and changes with probe position inside an aerosol gas flow. Electron density (n{sub e}) is in the range 10{sup 8}--10{sup 10} {sup {minus}cm }at the skimmer tip and drops abruptly to 10{sup 6}--10{sup 8} cm{sup {minus}3} near the skimmer tip and drops abruptly to 10{sup 6}--10{sup 8} cm{sup {minus}3} downstream further behind the skimmer. Electron density in the beam leaving the skimmer also depends on water loading and on the presence and mass of matrix elements. Axially resolved distributions of electron number-density and electron temperature were obtained to characterize the ion beam at a variety of plasma operating conditions. The electron density dropped by a factor of 101 along the centerline between the sampler and skimmer cones in the first stage and continued to drop by factors of 10{sup 4}--10{sup 5} downstream of skimmer to the entrance of ion lens. The electron density in the beam expansion behind sampler cone exhibited a 1/z{sup 2} intensity fall-off (z is the axial position). An second beam expansion originated from the skimmer entrance, and the beam flow underwent with another 1/z{sup 2} fall-off behind the skimmer. Skimmer interactions play an important role in plasma extraction in the ICP-MS instrument.

  17. IEEE International conference on plasma science: Conference record--Abstracts

    SciTech Connect

    Not Available

    1993-01-01

    The conference covered the following topics: basic plasma physics; vacuum electronics; gaseous and electrical gas discharges; laser-produced plasma; space plasmas; computational plasma science; plasma diagnostics; electron, ion and plasma sources; intense electron and ion beams; intense beam microwaves; fast wave M/W devices; microwave-plasma interactions; magnetic fusion; MHD; plasma focus; ultrafast z-pinches and x-ray lasers; plasma processing; fast-opening switches; EM and ETH launchers; solid-state plasmas and switches; plasmas for lighting; ball lightning and spherical plasma configurations; and environmental/energy issues. Separate abstracts were prepared for 379 items in this conference.

  18. Method for reducing peak phase current and decreasing staring time for an internal combustion engine having an induction machine

    DOEpatents

    Amey, David L.; Degner, Michael W.

    2002-01-01

    A method for reducing the starting time and reducing the peak phase currents for an internal combustion engine that is started using an induction machine starter/alternator. The starting time is reduced by pre-fluxing the induction machine and the peak phase currents are reduced by reducing the flux current command after a predetermined period of time has elapsed and concurrent to the application of the torque current command. The method of the present invention also provides a strategy for anticipating the start command for an internal combustion engine and determines a start strategy based on the start command and the operating state of the internal combustion engine.

  19. ICPP: Low-frequency, inductively coupled plasma sources: operation and applications

    NASA Astrophysics Data System (ADS)

    Xu, Shuyan

    2000-10-01

    Low-frequency, inductively coupled plasmas (LFICP) have recently attracted great attention in connection with the plasma processing of materials. The low-frequency sources feature high plasma density (10^18 - 10^19 m-3), excellent uniformity over large areas, low electron temperature, moderate plasma potential, deeper RF filed penetration and high power transfer efficiency. This work presents a comprehensive experimental and theoretical investigation of the electric/electromagnetic properties, electron density and temperature, and the optical emission in 500 kHz ICP sources. A series of experiments conducted in Ar/N_2/H2 and CH4 discharges show that the high-density plasmas are generated in the two distinctive E- and H- operating regimes. Near the mode transitions the power reflection coefficient exhibits resonant minima. The optical emission spectra of neutral atoms and ions together with global power balance arguments reveal that the step-wise ionization via excited states can be responsible for delaying the backward transition between the H- and E- discharge states, and, hence, lead to hysteresis. The experimental and theoretical results on the discharge mode transitions and hysteresis are discussed as well. It is demonstrated that the low-frequency ICP source is extremely efficient for nitriding of solid materials, especially of stainless steel. A low-temperature ( 350^oC) steel nitriding experiments undertaken in plasmas of various Ar/N_2/H2 gas mixtures show that very high nitriding rates, ranging from 40 μm/hour (stainless steel AISI304) to 90 μm/hour (AISI410), can be achieved. The microstructure, phases and composition of the nitrided surface layers have been characterized by Scanning Electron Microscopy, x-ray photoelectron spectroscopy, x-ray diffraction spectroscopy and energy dispersive x-ray spectroscopy. It has been shown that the crystalline phases of the nitrided layer can efficiently be controlled by the processing conditions. The nitrogen

  20. The Spatial Effects of Antenna Configuration in a Large Area Inductively Coupled Plasma System for Flat Panel Displays

    NASA Astrophysics Data System (ADS)

    Seon-Geun, Oh; Young-Jun, Lee; Jae-Hong, Jeon; Jong-Hyeon, Seo; Hee-Hwan, Choe

    2014-08-01

    Spatial distributions of plasma parameters such as electron density, electron temperature and electric potential were investigated using a commercial simulation software (COMSOLTM) to predict the effects of antenna configuration in a large area inductively coupled plasma (ICP) system for flat panel displays. Nine planar antenna sets were evenly placed above a ceramic window. While the electron density was influenced by both the input current and gas pressure, the electron temperature and electric potential were dominantly affected by the gas pressure.

  1. Probabilistic Analysis of International Space Station Plasma Interaction

    NASA Astrophysics Data System (ADS)

    Reddell, B.; Alred, J.; Kramer, L.; Mikatarian, R.; Minow, J.; Koontz, S.

    2005-12-01

    To date, the International Space Station (ISS) has been one of the largest objects flown in lower earth orbit (LEO). The ISS utilizes high voltage solar arrays (160V) that are negatively grounded leading to pressurized elements that can float negatively with respect to the plasma. Because laboratory measurements indicate a dielectric breakdown potential difference of 80V, arcing could occur on the ISS structure. To overcome the possibility of arcing and clamp the potential of the structure, two Plasma Contactor Units (PCUs) were designed, built, and flown. Also a limited amount of measurements of the floating potential for the present ISS configuration were made by a Floating Potential Probe (FPP), indicating a minimum potential of -24 Volts at the measurement location. A predictive tool, the ISS Plasma Interaction Model (PIM) has been developed accounting for the solar array electron collection, solar array mast wire and effective conductive area on the structure. The model has been used for predictions of the present ISS configuration. The conductive area has been inferred based on available floating potential measurements. Analysis of FPP and PCU data indicated distribution of the conductive area along the Russian segment of the ISS structure. A significant input to PIM is the plasma environment. The International Reference Ionosphere (IRI 2001) was initially used to obtain plasma temperature and density values. However, IRI provides mean parameters, leading to difficulties in interpretation of on-orbit data, especially at eclipse exit where maximum charging can occur. This limits our predicative capability. Satellite and Incoherent Scatter Radar (ISR) data of plasma parameters have also been collected. Approximately 130,000 electron temperature (Te) and density (Ne) pairs for typical ISS eclipse exit conditions have been extracted from the reduced Langmuir probe data flown aboard the NASA DE-2 satellite. Additionally, another 18,000 Te and Ne pairs of ISR data

  2. The structural and optical properties of black silicon by inductively coupled plasma reactive ion etching

    NASA Astrophysics Data System (ADS)

    Steglich, Martin; Käsebier, Thomas; Zilk, Matthias; Pertsch, Thomas; Kley, Ernst-Bernhard; Tünnermann, Andreas

    2014-11-01

    Black Silicon nanostructures are fabricated by Inductively Coupled Plasma Reactive Ion Etching (ICP-RIE) in a gas mixture of SF6 and O2 at non-cryogenic temperatures. The structure evolution and the dependency of final structure geometry on the main processing parameters gas composition and working pressure are investigated and explained comprehensively. The optical properties of the produced Black Silicon structures, a distinct antireflection and light trapping effect, are resolved by optical spectroscopy and conclusively illustrated by optical simulations of accurate models of the real nanostructures. By that the structure sidewall roughness is found to be critical for an elevated reflectance of Black Silicon resulting from non-optimized etching processes. By analysis of a multitude of structures fabricated under different conditions, approximate limits for the range of feasible nanostructure geometries are derived. Finally, the technological applicability of Black Silicon fabrication by ICP-RIE is discussed.

  3. Collisionality scaling of turbulence and transport in advanced inductive plasmas in DIII-D

    NASA Astrophysics Data System (ADS)

    Yan, Z.; McKee, G. R.; Petty, C.; Luce, T.; Chen, X.; Holland, C.; Rhodes, T.; Schmitz, L.; Wang, G.; Zeng, L.; Marinoni, A.; Solomon, W.; DIII-D Team

    2015-11-01

    The collisionality scaling of multiscale turbulence properties and thermal transport characteristics in high-beta, high confinement Advanced Inductive (AI) plasmas was determined via systematic dimensionless scaling experiments on DIII-D. Preliminary estimate indicates a weak collisionality dependence of energy confinement as v* varied by a factor of ~2. Electron density and scaled (~Bt2) temperature profiles are well matched in the scan. Interestingly, low-k density fluctuation amplitudes are observed to decrease at lower v* near ρ ~ 0 . 75 . Ion and electron thermal transport values, computed with ONETWO using experimentally measured profiles and sources, will be presented, along with multi-scale turbulence measurements obtained with various fluctuation diagnostics. Altering collisionality should change the relative contribution of different modes to transport.

  4. III-Nitride Dry Etching - Comparison of Inductively Coupled Plasma Chemistries

    SciTech Connect

    Abernathy, C.R.; Cho, H.; Donovan, S.M.; Hahn, Y-B.; Han, J.; Hays, D.C.; MacKenzie, J.D.; Pearton, S.J.; Shul, R.J.

    1998-11-10

    A systematic study of the etch characteristics of GaN, AlN and InN has been performed with boron halides- (BI{sub 3} and BBr{sub 3}) and interhalogen- (ICl and IBr) based Inductively Coupled Plasmas. Maximum etch selectivities of -100:1 were achieved for InN over both GaN and AlN in the BI{sub 3} mixtures due to the relatively high volatility of the InN etch products and the lower bond strength of InN. Maximum selectivies of- 14 for InN over GaN and >25 for InN over AlN were obtained with ICl and IBr chemistries. The etched surface morphologies of GaN in these four mixtures are similar or better than those of the control sample.

  5. Automation of preparation of nonmetallic samples for analysis by atomic absorption and inductively coupled plasma spectrometry

    NASA Technical Reports Server (NTRS)

    Wittmann, A.; Willay, G.

    1986-01-01

    For a rapid preparation of solutions intended for analysis by inductively coupled plasma emission spectrometry or atomic absorption spectrometry, an automatic device called Plasmasol was developed. This apparatus used the property of nonwettability of glassy C to fuse the sample in an appropriate flux. The sample-flux mixture is placed in a composite crucible, then heated at high temperature, swirled until full dissolution is achieved, and then poured into a water-filled beaker. After acid addition, dissolution of the melt, and filling to the mark, the solution is ready for analysis. The analytical results obtained, either for oxide samples or for prereduced iron ores show that the solutions prepared with this device are undistinguished from those obtained by manual dissolutions done by acid digestion or by high temperature fusion. Preparation reproducibility and analytical tests illustrate the performance of Plasmasol.

  6. Power dependence of electron density at various pressures in inductively coupled plasmas

    SciTech Connect

    Kim, June Young; Kim, Dong-Hwan; Kim, Ju Ho; Jeon, Sang-Bum; Cho, Sung-Won; Chung, Chin-Wook

    2014-11-15

    Experimental observation of the electron density variation in inductively coupled plasmas with the electron energy probability function (EEPFs) was performed at various gas pressures at two RF powers (25 W and 200 W). The measured EEPFs at high power discharges (200 W) showed a Maxwellian distribution, while evolution of the EEPFs from a bi-Maxwellian distribution to a Druyvesteyn-like distribution was observed at low RF powers (25 W) with increasing pressure. A discrepancy of the electron density variation between the two RF powers was observed. This difference is explained by the modified collisional loss and the Bohm velocity from the EEPF of the bi-Maxwellian distribution and the Druyvesteyn–like distribution.

  7. Effect of the electron energy distribution on total energy loss with argon in inductively coupled plasmas

    SciTech Connect

    Kim, June Young; Kim, Young-Cheol; Kim, Yu-Sin; Chung, Chin-Wook

    2015-01-15

    The total energy lost per electron-ion pair lost ε{sub T} is investigated with the electron energy distribution function (EEDF). The EEDFs are measured at various argon powers in RF inductively coupled plasma, and the EEDFs show a depleted distribution (a discontinuity occurring at the minimum argon excitation threshold energy level) with the bulk temperature and the tail temperature. The total energy loss per electron-ion pair lost ε{sub T} is calculated from a power balance model with the Maxwellian EEDFs and the depleted EEDFs and then compared with the measured ε{sub T} from the floating probe. It is concluded that the small population of the depleted high energy electrons dramatically increases the collisional energy loss, and the calculated ε{sub T} from the depleted EEDFs has a value that is similar to the measured ε{sub T}.

  8. Osmium isotopic ratio measurements by inductively coupled plasma source mass spectrometry

    SciTech Connect

    Russ, G.P. III; Bazan, J.M.; Date, A.R.

    1987-04-01

    The isotopic composition of nanogram quantities of osmium was measured by using an inductively coupled plasma source mass spectrometer. Sensitivity was enhanced a factor of approx.100 by the use of an osmium tetraoxide vapor generator rather than nebulization of solution. For samples less than or equal to5 ng, the ratios /sup 190/Os//sup 192/Os, /sup 189/Os//sup 192/Os, and /sup 188/Os//sup 192/Os were determined to better than +/- 0.5% (1sigma/sub m/) precision. For the minor isotopes, the ratios /sup 187/Os//sup 192/Os and /sup 186/Os//sup 192/Os were determined to +/-1%, and /sup 184/Os//sup 192/Os (4 x 10/sup -4/) was determined to approx.10%. Isotope ratios for common osmium are reported.

  9. Pulsed radio-frequency discharge inductively coupled plasma mass spectrometry for oxide analysis

    NASA Astrophysics Data System (ADS)

    Li, Weifeng; Yin, Zhibin; Hang, Wei; Li, Bin; Huang, Benli

    2016-08-01

    A direct solid sampling technique has been developed based on a pulsed radio-frequency discharge (RFD) in mixture of N2 and Ar environment at atmospheric pressure. With an averaged input power of 65 W, a crater with the diameter of 80 μm and depth of 50 μm can be formed on sample surface after discharge for 1 min, suggesting the feasibility of the pulsed RFD for sampling nonconductive solids. Combined with inductively coupled plasma mass spectrometry (ICPMS), this technique allows to measure elemental composition of solids directly with relative standard deviation (RSD) of ~ 20%. Capability of quantitative analysis was demonstrated by the use of soil standards and artificial standards. Good calibration linearity and limits of detection (LODs) in range of 10- 8-10- 9 g/g were achieved for most elements.

  10. Ionization in inductively coupled argon plasmas studied by optical emission spectroscopy

    SciTech Connect

    Lee, Young-Kwang; Chung, Chin-Wook

    2011-01-01

    Contribution of stepwise ionization to total ionization was experimentally investigated in low-pressure inductively coupled argon plasmas. In the pressure range 3-50 mTorr, optical emission spectroscopy was employed to determine metastable fractions (metastable density relative to ground state density) by measuring the emission intensity of selected lines. The measured metastable fractions were in good agreement with the calculation, showing a dependence on the discharge pressure. The rate of stepwise ionization was estimated from the excited level densities (measurements and model predictions) and their ionization rate coefficients. It is observed that at relatively low discharge pressures (<10 mTorr) the ionization is mainly provided by the direct ionization, whereas at higher pressure the stepwise ionization is predominant with increasing absorbed power.

  11. Multi-elemental analysis of aqueous geological samples by inductively coupled plasma-optical emission spectrometry

    USGS Publications Warehouse

    Todorov, Todor I.; Wolf, Ruth E.; Adams, Monique

    2014-01-01

    Typically, 27 major, minor, and trace elements are determined in natural waters, acid mine drainage, extraction fluids, and leachates of geological and environmental samples by inductively coupled plasma-optical emission spectrometry (ICP-OES). At the discretion of the analyst, additional elements may be determined after suitable method modifications and performance data are established. Samples are preserved in 1–2 percent nitric acid (HNO3) at sample collection or as soon as possible after collection. The aqueous samples are aspirated into the ICP-OES discharge, where the elemental emission signals are measured simultaneously for 27 elements. Calibration is performed with a series of matrix-matched, multi-element solution standards.

  12. Assessment of the analytical capabilities of inductively coupled plasma-mass spectrometry

    USGS Publications Warehouse

    Taylor, H.E.; Garbarino, J.R.

    1988-01-01

    A thorough assessment of the analytical capabilities of inductively coupled plasma-mass spectrometry was conducted for selected analytes of importance in water quality applications and hydrologic research. A multielement calibration curve technique was designed to produce accurate and precise results in analysis times of approximately one minute. The suite of elements included Al, As, B, Ba, Be, Cd, Co, Cr, Cu, Hg, Li, Mn, Mo, Ni, Pb, Se, Sr, V, and Zn. The effects of sample matrix composition on the accuracy of the determinations showed that matrix elements (such as Na, Ca, Mg, and K) that may be present in natural water samples at concentration levels greater than 50 mg/L resulted in as much as a 10% suppression in ion current for analyte elements. Operational detection limits are presented.

  13. Automated standardization technique for an inductively-coupled plasma emission spectrometer

    USGS Publications Warehouse

    Garbarino, J.R.; Taylor, H.E.

    1982-01-01

    The manifold assembly subsystem described permits real-time computer-controlled standardization and quality control of a commercial inductively-coupled plasma atomic emission spectrometer. The manifold assembly consists of a branch-structured glass manifold, a series of microcomputer-controlled solenoid valves, and a reservoir for each standard. Automated standardization involves selective actuation of each solenoid valve that permits a specific mixed standard solution to be pumped to the nebulizer of the spectrometer. Quality control is based on the evaluation of results obtained for a mixed standard containing 17 analytes, that is measured periodically with unknown samples. An inaccurate standard evaluation triggers restandardization of the instrument according to a predetermined protocol. Interaction of the computer-controlled manifold assembly hardware with the spectrometer system is outlined. Evaluation of the automated standardization system with respect to reliability, simplicity, flexibility, and efficiency is compared to the manual procedure. ?? 1982.

  14. Determination of mercury in fish samples by slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Liaw, Ming-Jyh; Jiang, Shiuh-Jen; Li, Yi-Ching

    1997-06-01

    Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry (USS-ETV-ICP-MS) has been applied to the determination of mercury in several fish samples. The effects of instrument operating conditions and slurry preparation on the ion signals are reported. Palladium was used as modifier to delay the vaporization of mercury in this study. As the vaporization behavior of mercury in fish slurry and aqueous solution is quite different, the standard addition method was used for the determination of mercury in reference materials. The detection limit of mercury estimated from the standard addition curve was in the range 0.002-0.004 μg g -1 for different samples. This method has been applied to the determination of mercury in dogfish muscle reference material (DORM-1 and DORM-2) and dogfish liver reference material (DOLT-1). Accuracy was better than 4% and precision was better than 7% with the USS-ETV-ICP-MS method.

  15. Stable isotope dilution analysis of hydrologic samples by inductively coupled plasma mass spectrometry

    USGS Publications Warehouse

    Garbarino, J.R.; Taylor, H.E.

    1987-01-01

    Inductively coupled plasma mass spectrometry is employed in the determination of Ni, Cu, Sr, Cd, Ba, Ti, and Pb in nonsaline, natural water samples by stable isotope dilution analysis. Hydrologic samples were directly analyzed without any unusual pretreatment. Interference effects related to overlapping isobars, formation of metal oxide and multiply charged ions, and matrix composition were identified and suitable methods of correction evaluated. A comparability study snowed that single-element isotope dilution analysis was only marginally better than sequential multielement isotope dilution analysis. Accuracy and precision of the single-element method were determined on the basis of results obtained for standard reference materials. The instrumental technique was shown to be ideally suited for programs associated with certification of standard reference materials.

  16. Multielement analysis of deep-sea sediments by inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Xia, Ning; Wu, Zhaohui; Guo, Dongfa; Yao, De

    2008-05-01

    Marine sediments were dissolved by HNO3-HF-HClO4 in a sealed container at low pressure; HF was evaporated in an open container and salts were dissolved in HCl by heating, then transferred to 2% HNO3 solution. A total of 45 elements, including Li, Be, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, Rb, Sr, Y, Zr, Nb, Mo, Cd, In, Sb, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Tl, Pb, Bi, Th and U, were measured by inductively coupled plasma mass spectrometry (ICP-MS). Conditions and sample experiments showed that this procedure defines a good experimental method which has the advantages of clear interference, easy operation and reliable results. The concentrations of the 45 elements could be used for resource exploration, environmental assessment and academic research.

  17. Trace elemental composition of curry by inductively coupled plasma optical emission spectrometry (ICP-OES).

    PubMed

    Gonzálvez, A; Armenta, S; De La Guardia, M

    2008-01-01

    A methodology based on inductively coupled plasma optical emission spectrometry (ICP-OES) after microwave-assisted acid digestion was developed to determine the content of traces elements in curry samples from the Spanish market. The methodology was validated in terms of accuracy by the analysis of citrus and tomato leaf reference materials achieving comparable results with the certified values. The trace metal content of curry samples was compared with data available from previously published reports concerning Indian samples, especially in terms of heavy metal composition, in order to guarantee the quality of the commercially available spices in the European countries. Values found for the analysis of arsenic, lead and cadmium were significantly lower than the maximum limit allowed by European Union statutory limits for heavy metals and lower than those obtained for Indian curry leaves reported by Indian research teams by using neutron activation and γ-ray analysis. PMID:24784807

  18. Study of uranium matrix interference on ten analytes using inductively coupled plasma atomic emission spectrometry

    NASA Astrophysics Data System (ADS)

    Ghazi, A. A.; Qamar, Sajid; Atta, M. A.

    1993-08-01

    Maximum allowable concentrations of 12 elements in uranium hexafluoride feed for enrichment to reactor grade material (about 3%), vary from 1 to 100 ppm ( μg/g). Using an inductively coupled plasma atomic emission spectrometer, 51 lines of ten of these elements (B, Cr, Mo, P, Sb, Si, Ta, Ti, V and W) have been studied with a uranium matrix to investigate the matrix interference on the basis of signal to background (SBR), and background to background ratios (BBR). Detection limits and limits of quantitative determination (LQDs) were calculated for these elements in a uranium matrix using SBR and relative standard deviation of the background signal (RSD B) approach. In almost all cases, the uranium matrix interference reduces the SBRs to the extent that direct trace analysis is impossible. A uranium sample having known concentrations of impurities (around LQDs) was directly analysed with results that showed reasonable accuracy and precision.

  19. Accurate determination of silver nanoparticles in animal tissues by inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Veverková, Lenka; Hradilová, Šárka; Milde, David; Panáček, Aleš; Skopalová, Jana; Kvítek, Libor; Petrželová, Kamila; Zbořil, Radek

    2014-12-01

    This study examined recoveries of silver determination in animal tissues after wet digestion by inductively coupled plasma mass spectrometry. The composition of the mineralization mixture for microwave assisted digestion was optimized and the best recoveries were obtained for mineralization with HNO3 and addition of HCl promptly after digestion. The optimization was performed on model samples of chicken meat spiked with silver nanoparticles and a solution of ionic silver. Basic calculations of theoretical distribution of Ag among various silver-containing species were implemented and the results showed that most of the silver is in the form of soluble complexes AgCl2- and AgCl32 - for the optimized composition of the mineralization mixture. Three animal tissue certified reference materials were then analyzed to verify the trueness and precision of the results.

  20. Etching characteristics of LiNbO3 in reactive ion etching and inductively coupled plasma

    NASA Astrophysics Data System (ADS)

    Ren, Z.; Heard, P. J.; Marshall, J. M.; Thomas, P. A.; Yu, S.

    2008-02-01

    The etching characteristics of congruent LiNbO3 single crystals including doped LiNbO3 and proton-changed LiNbO3 have been studied in reactive ion etching (RIE) and inductively coupled plasma (ICP) etching tools, using different recipes of gas mixtures. The effects of parameters including working pressure, RIE power, and ICP power are investigated and analyzed by measurement of etching depth, selectivity, uniformity, etched surface state, and sidewall profile by means of focused ion beam etching, energy-dispersive x-ray analysis, secondary ion mass spectroscopy, scanning electron microscopy, and surface profilometry. The effects of a sample carrier wafer coating have also been investigated. Optimized processes with high etching rates, good mask selectivity, and a near-vertical profile have been achieved. Ridge waveguides on proton-exchanged LiNbO3 have been fabricated and optically measured.

  1. Inductively coupled plasma-atomic emission spectrometry (ICP-AES) in support of nuclear waste management

    NASA Astrophysics Data System (ADS)

    Huff, Edmund A.; Horwitz, E. Philip

    Simulated complex nuclear waste solutions are characterized by inductively coupled plasma-atomic emission spectrometry (ICP-AES). Simultaneous and sequential measurements are made of liquid extraction distribution coefficients needed in the development of process flow sheets for component separations. This paper describes the determination of 19 elements, comprised of process contaminants (Al, Cr, Fe, Ni) and nuclear fission products (Ba, Cd, Ce, Eu, La, Mo, Nd, Pd, Pr, Rh, Ru, Sm, Sr, Y, Zr), in diverse aqueous streams. The concentrations determined vary from 0.04 to 4000μg ml -1 with dilutions being used to bring analytical measurements into the range of calibration standards. The estimated precision and accuracy of the method are 1-5 %. Data are presented on recoveries and material balances for extraction systems that can be used for the implementation of actinide (III)-fission product separation schemes.

  2. Neutralization efficiency estimation in a neutral beam source based on inductively coupled plasma

    NASA Astrophysics Data System (ADS)

    Vozniy, O. V.; Yeom, G. Y.

    2009-01-01

    This study examined the optimal conditions of neutral beam generation to maintain a high degree of neutralization and focusing during beam energy variation for a neutral beam source based on inductively coupled plasma with a three-grid ion beam acceleration system. The neutral beam energy distribution was estimated by measuring the energy profiles of ions that "survived" the neutralization after reflection. The energy measurements of the primary and reflected ions showed narrow distribution functions, each with only one peak. At higher beam energies, both the ratio of the ion energy loss to the primary energy and the degree of energy divergence decreased, confirming the precise alignment of the neutral beam. The neutralization efficiency of the neutral beam source with a three-grid acceleration system was found to be affected mainly by the beam angle divergence rather than by the particle translation energy.

  3. Anisotropic Ta{sub 2}O{sub 5} waveguide etching using inductively coupled plasma etching

    SciTech Connect

    Muttalib, Muhammad Firdaus A. Chen, Ruiqi Y.; Pearce, Stuart J.; Charlton, Martin D. B.

    2014-07-01

    Smooth and vertical sidewall profiles are required to create low loss rib and ridge waveguides for integrated optical device and solid state laser applications. In this work, inductively coupled plasma (ICP) etching processes are developed to produce high quality low loss tantalum pentoxide (Ta{sub 2}O{sub 5}) waveguides. A mixture of C{sub 4}F{sub 8} and O{sub 2} gas are used in combination with chromium (Cr) hard mask for this purpose. In this paper, the authors make a detailed investigation of the etch process parameter window. Effects of process parameters such as ICP power, platen power, gas flow, and chamber pressure on etch rate and sidewall slope angle are investigated. Chamber pressure is found to be a particularly important factor, which can be used to tune the sidewall slope angle and so prevent undercut.

  4. Alleviation of overlap interferences for determination of potassium isotope ratios by inductively coupled plasma mass spectrometry

    SciTech Connect

    Jiang, S.J.; Houk, R.S.; Stevens, M.A.

    1988-06-01

    Positioning the sampling orifice relatively far from the load coil combined with use of low forward power and high aerosol gas flow rate causes the background mass spectrum to become dominated by NO/sup +/. Nearly all the Ar/sup +/ and ArH/sup +/ ions are suppressed under these conditions, which frees m/z 39 and 41 for potassium isotope ratio measurements. The precision is 0.3-0.9% relative standard deviation for potassium concentrations in the range 1-50 mg L/sup -1/. The determined ratios are approx. 9% higher than the accepted value and also vary with the concentration of sodium concomitant, so calibrations and chemical separations are desirable. These observations should permit use of inductively coupled plasma mass spectrometry for rapid isotope ratio determinations of potassium from biological organisms or water sources.

  5. Inductively coupled plasma optical emission spectroscopy determination of trace element composition of argan oil.

    PubMed

    Gonzálvez, A; Ghanjaoui, M E; El Rhazi, M; de la Guardia, M

    2010-02-01

    A methodology based on inductively coupled plasma optical emission spectroscopy (ICP-OES) after microwave assisted acid digestion has been developed to determine the trace element content of Moroccan argan oil. Limit of detection values equal or lower than few mg/kg were obtained for all elements under study. To assure the accuracy of the whole procedure, recovery studies were carried out on argan oil samples spiked at different concentration levels from 10 to 200 µg/L. Quantitative average recovery values were obtained for all elements evaluated, demonstrating the suitability of this methodology for the determination of trace elements in argan oil samples. Aluminum, calcium, chromium, iron, potassium, lithium, magnesium, sodium, vanadium and zinc were quantitatively determined in Moroccan argan oils being found that their concentration is different of that found in other edible oils thus offering a way for authentication and for the evaluation of possible adulterations. PMID:21339122

  6. Laser Irradiation of Aqueous Solutions for Application in Inductively Coupled Plasma Spectrometry

    NASA Astrophysics Data System (ADS)

    Su, H.; Xu, L.; Chen, J.; Li, X.; Wang, Y.

    2016-01-01

    The sensitivity of detection of trace heavy metal elements in water samples by inductively coupled plasma (ICP) spectrometry has been improved applying a 10.6 μm infrared laser to irradiate the aqueous solution. With optimal laser power density and irradiation time, the surface tension and viscosity of the aqueous solution were reduced by 38.09 and 11.35%, respectively. The nebulization efficiency of the processed solution in ICP was increased by 47.14%. The spectral intensity and signal-to-noise ratio (SNR) of the trace heavy metal elements including As, Cd, Cr, Cu, Hg, and Pb in the treated aqueous solution were both increased. Our experiment demonstrated that irradiation using an infrared laser at 10.6 μm is a simple and effective method to improve the detection sensitivity of ICP spectrometry for trace heavy metal elements.

  7. [A genetic algorithm approach to qualitative analysis in inductively coupled plasma-atomic emission spectroscopy].

    PubMed

    Peng, Bin; Liu, Ke-ling; Li, Zhi-min; Wang, Yue-song; Huang, Tu-jiang

    2002-06-01

    Genetic algorithm (GA) is used in automatic qualitative analysis by a sequential inductively coupled plasma spectrometer (ICP-AES) and a computer program is developed in this paper. No any standard samples are needed, and spectroscopic interferences can be eliminated. All elements and their concentration ranges of an unknown sample can be reported. The replication rate Pr, crossover rate Pc, and mutation rate of the genetic algorithm were adjusted to be 0.6, 0.4 and 0 respectively. The analytical results of GA are in good agreement with the reference values. It indicates that, combined with the intensity information, the GA can be applied to spectroscopic qualitative analysis and expected to become an effective method in qualitative analysis in ICP-AES after further work. PMID:12938334

  8. Thin-layer chromatography combined with diode laser thermal vaporization inductively coupled plasma mass spectrometry.

    PubMed

    Bednařík, Antonín; Tomalová, Iva; Kanický, Viktor; Preisler, Jan

    2014-10-17

    Here we present a novel coupling of thin-layer chromatography (TLC) to diode laser thermal vaporization inductively coupled plasma mass spectrometry (DLTV ICP MS). DLTV is a new technique of aerosol generation which uses a diode laser to induce pyrolysis of a substrate. In this case the cellulose stationary phase on aluminum-backed TLC sheets overprinted with black ink to absorb laser light. The experimental arrangement relies on economic instrumentation: an 808-nm 1.2-W continuous-wave infrared diode laser attached to a syringe pump serving as the movable stage. Using a glass tubular cell, the entire length of a TLC separation channel is scanned. The 8-cm long lanes were scanned in ∼35 s. The TLC - DLTV ICP MS coupling is demonstrated on the separation of four cobalamins (hydroxo-; adenosyl-; cyano-; and methylcobalamin) with limits of detection ∼2 pg and repeatability ∼15% for each individual species. PMID:25193171

  9. Separation of actinides using capillary extraction chromatography-inductively coupled plasma mass spectrometry

    SciTech Connect

    Peterson, Dominic S

    2008-01-01

    Trace levels of actinides have been separated on extraction chromatography columns. Detection of the actinides was achieved using an inductively coupled plasma mass spectrometer (ICP-MS), which was coupled with the extraction chromatography system. In this study we compare 30 cm long, 4.6 mm ID columns to capillary columns (750 {micro}m ID) with lengths from 30 cm up to 150 cm. The columns that were tested were packed with TRU resin. We were able to separate a mixture of five actinides ({sup 232}Th, {sup 238}U, {sup 237}Np, {sup 239}pU, {sup 241}Am). This work has application to rapid bioassay as well as for automated separations of actinide materials.

  10. Inductively coupled plasma etching of HgCdTe IRFPAs detectors at cryogenic temperature

    NASA Astrophysics Data System (ADS)

    Chen, Y. Y.; Ye, Z. H.; Sun, C. H.; Zhang, S.; Hu, X. N.; Ding, R. J.; He, L.

    2016-05-01

    To fabricate various advanced structures with HgCdTe material, the Inductively Coupled Plasma enhanced Reactive Ion Etching system is indispensable. However, due to low damage threshold and complicated behaviors of mercury in HgCdTe, the lattice damage and induced electrical conversion is very common. According to the diffusion model during etching period, the mercury interstitials, however, may not diffuse deep into the material at cryogenic temperature. In this report, ICP etching of HgCdTe at cryogenic temperature was implemented. The etching system with cryogenic assembly is provided by Oxford Instrument. The sample table was cooled down to 123K with liquid nitrogen. The mask of SiO2 with a contact layer of ZnS functioned well at this temperature. The selectivity and etching velocity maintained the same as reported in the etching of room temperature. Smooth and clean surfaces and profiles were achieved with an optimized recipe.

  11. Neutralization efficiency estimation in a neutral beam source based on inductively coupled plasma

    SciTech Connect

    Vozniy, O. V.; Yeom, G. Y.

    2009-01-01

    This study examined the optimal conditions of neutral beam generation to maintain a high degree of neutralization and focusing during beam energy variation for a neutral beam source based on inductively coupled plasma with a three-grid ion beam acceleration system. The neutral beam energy distribution was estimated by measuring the energy profiles of ions that 'survived' the neutralization after reflection. The energy measurements of the primary and reflected ions showed narrow distribution functions, each with only one peak. At higher beam energies, both the ratio of the ion energy loss to the primary energy and the degree of energy divergence decreased, confirming the precise alignment of the neutral beam. The neutralization efficiency of the neutral beam source with a three-grid acceleration system was found to be affected mainly by the beam angle divergence rather than by the particle translation energy.

  12. Homogeneous nanocrystalline cubic silicon carbide films prepared by inductively coupled plasma chemical vapor deposition.

    PubMed

    Cheng, Qijin; Xu, S; Long, Jidong; Huang, Shiyong; Guo, Jun

    2007-11-21

    Silicon carbide films with different carbon concentrations x(C) have been synthesized by inductively coupled plasma chemical vapor deposition from a SiH(4)/CH(4)/H(2) gas mixture at a low substrate temperature of 500 °C. The characteristics of the films were studied by x-ray photoelectron spectroscopy, x-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, Fourier transform infrared absorption spectroscopy, and Raman spectroscopy. Our experimental results show that, at x(C) = 49 at.%, the film is made up of homogeneous nanocrystalline cubic silicon carbide without any phase of silicon, graphite, or diamond crystallites/clusters. The average size of SiC crystallites is approximately 6 nm. At a lower value of x(C), polycrystalline silicon and amorphous silicon carbide coexist in the films. At a higher value of x(C), amorphous carbon and silicon carbide coexist in the films. PMID:21730481

  13. Sorption concentration and inductively coupled plasma determination of Mo, V, Zr, and Cr in sea water

    SciTech Connect

    Shcherbinina, N.I.; Ishmiyarova, G.P.; Myasoedova, G.V.

    1992-02-10

    Sorption on complex-forming sorbents is an expanding method for the concentration of microelements for water analysis. The adsorbed elements can be determined directly in the concentrate, in the eluate after desorption or in the residue after decomposition of the sorbent. Among the methods used to determine the elements is atomic emission spectrometry from an inductively coupled plasma (ICP). This method is often used to determine relatively easily desorbed metals. In the present work, the authors investigate the concentration of Mo, V, Zr, and Cr(VI) with the complex forming sorbent POLIORGS VII M and their subsequent determination of ICP. These hard to desorb metals are put back into solution by the rapid microwave decomposition of the sorbent/concentrate with a HNO{sub 3}/H{sub 2}O{sub 2} mixture. The developed method for the determination of Mo, V, Zr, and Cr(VI) was used to analyze sea water. 14 refs., 1 fig., 6 tabs.

  14. Effect of the electron energy distribution on total energy loss with argon in inductively coupled plasmas

    NASA Astrophysics Data System (ADS)

    Kim, June Young; Kim, Young-Cheol; Kim, Yu-Sin; Chung, Chin-Wook

    2015-01-01

    The total energy lost per electron-ion pair lost ɛT is investigated with the electron energy distribution function (EEDF). The EEDFs are measured at various argon powers in RF inductively coupled plasma, and the EEDFs show a depleted distribution (a discontinuity occurring at the minimum argon excitation threshold energy level) with the bulk temperature and the tail temperature. The total energy loss per electron-ion pair lost ɛT is calculated from a power balance model with the Maxwellian EEDFs and the depleted EEDFs and then compared with the measured ɛT from the floating probe. It is concluded that the small population of the depleted high energy electrons dramatically increases the collisional energy loss, and the calculated ɛT from the depleted EEDFs has a value that is similar to the measured ɛT.

  15. Single and Multi-Pulse Low-Energy Conical Theta Pinch Inductive Pulsed Plasma Thruster Performance

    NASA Technical Reports Server (NTRS)

    Hallock, A. K.; Martin, A. K.; Polzin, K. A.; Kimberlin, A. C.; Eskridge, R. H.

    2013-01-01

    Impulse bits produced by conical theta-pinch inductive pulsed plasma thrusters possessing cone angles of 20deg, 38deg, and 60deg, were quantified for 500J/pulse operation by direct measurement using a hanging-pendulum thrust stand. All three cone angles were tested in single-pulse mode, with the 38deg model producing the highest impulse bits at roughly 1 mN-s operating on both argon and xenon propellants. A capacitor charging system, assembled to support repetitively-pulsed thruster operation, permitted testing of the 38deg thruster at a repetition-rate of 5 Hz at power levels of 0.9, 1.6, and 2.5 kW. The average thrust measured during multiple-pulse operation exceeded the value obtained when the single-pulse impulse bit is multiplied by the repetition rate.

  16. Inductively Coupled Plasma: Fundamental Particle Investigations with Laser Ablation and Applications in Magnetic Sector Mass Spectrometry

    SciTech Connect

    Saetveit, Nathan Joe

    2008-01-01

    Particle size effects and elemental fractionation in laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) are investigated with nanosecond and femtosecond laser ablation, differential mobility analysis, and magnetic sector ICP-MS. Laser pulse width was found to have a significant influence on the LA particle size distribution and the elemental composition of the aerosol and thus fractionation. Emission from individual particles from solution nebulization, glass, and a pressed powder pellet are observed with high speed digital photography. The presence of intact particles in an ICP is shown to be a likely source of fractionation. A technique for the online detection of stimulated elemental release from neural tissue using magnetic sector ICP-MS is described. Detection limits of 1 μg L-1 or better were found for P, Mn, Fe, Cu, and Zn in a 60 μL injection in a physiological saline matrix.

  17. Induction thermal plasma synthesis of lithium oxide composite nanoparticles with a spinel structure

    NASA Astrophysics Data System (ADS)

    Sone, Hirotaka; Kageyama, Takuya; Tanaka, Manabu; Okamoto, Daisuke; Watanabe, Takayuki

    2016-07-01

    Li–Mn composite oxide nanoparticles are synthesized using an induction thermal plasma, and the formation mechanism is investigated on the basis of the homogenous nucleation rate and thermodynamic considerations. Under a high O2 partial pressure, MnO crystals nucleate and Li oxide condenses on MnO nuclei at a relatively high rate, forming LiMn2O4 in a single phase. On the other hand, under a low partial pressure of O2, LiMnO2 is obtained owing to the low condensation rate of Li oxide. This study presents the successful selective synthesis of LiMn2O4 nanoparticles by controlling the partial pressure of O2.

  18. Calculation of the Non-Inductive Current Profile in High-Performance NSTX Plasmas

    SciTech Connect

    Gerhardt, S P; Gates, D; Kaye, S; Menard, J; Bell, M G; Bell, R E; Le Blanc, B P; Kugel, H; Sabbagh, S A

    2011-02-09

    The constituents of the current profile have been computed for a wide range of high-performance plasmas in NSTX [M. Ono, et al., Nuclear Fusion 40, 557 (2000)]; these include cases designed to maximize the non-inductive fraction, pulse length, toroidal-β, or stored energy. In the absence of low-frequency MHD activity, good agreement is found between the reconstructed current profile and that predicted by summing the independently calculated inductive, pressure-driven, and neutral beam currents, without the need to invoke any anomalous beam ion diffusion. Exceptions occur, for instance, when there are toroidal Alfven eigenmode avalanches or coupled m/n=1/1+2/1 kink-tearing modes. In these cases, the addition of a spatially and temporally dependent fast ion diffusivity can reduce the core beam current drive, restoring agreement between the reconstructed profile and the summed constituents, as well as bringing better agreement between the simulated and measured neutron emission rate. An upper bound on the fast ion diffusivity of ~0.5-1 m2/sec is found in “MHD-free” discharges, based on the neutron emission, time rate of change of the neutron signal when a neutral beam is stepped, and reconstructed on-axis current density.

  19. Calculation of the non-inductive current profile in high-performance NSTX plasmas

    NASA Astrophysics Data System (ADS)

    Gerhardt, S. P.; Fredrickson, E.; Gates, D.; Kaye, S.; Menard, J.; Bell, M. G.; Bell, R. E.; Le Blanc, B. P.; Kugel, H.; Sabbagh, S. A.; Yuh, H.

    2011-03-01

    The constituents of the current profile have been computed for a wide range of high-performance plasmas in NSTX (Ono et al 2000 Nucl. Fusion 40 557); these include cases designed to maximize the non-inductive fraction, pulse length, toroidal-β or stored energy. In the absence of low-frequency MHD activity, good agreement is found between the reconstructed current profile and that predicted by summing the independently calculated inductive, pressure-driven and neutral beam currents, without the need to invoke any anomalous beam ion diffusion. Exceptions occur, for instance, when there are toroidal Alfvén eigenmode avalanches or coupled m/n = 1/1 + 2/1 kink-tearing modes. In these cases, the addition of a spatially and temporally dependent fast-ion diffusivity can reduce the core beam current drive, restoring agreement between the reconstructed profile and the summed constituents, as well as bringing better agreement between the simulated and measured neutron emission rate. An upper bound on the fast-ion diffusivity of ~0.5-1 m2 s-1 is found in 'MHD-free' discharges, based on the neutron emission, the time rate of change in the neutron signal when a neutral beam is stepped and reconstructed on-axis current density.

  20. Biomonitoring of hair samples by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS)

    NASA Astrophysics Data System (ADS)

    Sela, H.; Karpas, Z.; Zoriy, M.; Pickhardt, C.; Becker, J. S.

    2007-03-01

    An analytical method for determining essential elements (Zn, Fe and Cu) and toxic elements (Cr, Pb and U) on single hair strands by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-SFMS) using a double focusing sector field mass spectrometer was developed. Results obtained directly using LA-ICP-SFMS of hair were compared with those measured by inductively coupled plasma quadrupole mass spectrometry (ICP-QMS) of solutions of digested hair samples and the analytical methods were found to agree well. Different quantification strategies for trace element determination in hair samples such as external calibration, standard addition and isotope dilution were compared and demonstrated for uranium. For uranium determination in powdered hair by LA-ICP-MS solution-based calibration was applied by coupling the laser ablation chamber to an ultrasonic nebulizer. The significance of single hair analysis by LA-ICP-SFMS was demonstrated by a case study of a person who changed living environment. Differences in the uranium content observed along the single hair strand correlated with the changes in the level of uranium in drinking water. The uranium concentration in a single hair decreased from 212 to 18 ng g-1 with a change in the uranium concentration in drinking water from 2000 to 30 ng l-1. In addition, measurements of uranium isotope ratios showed a natural isotopic composition throughout the whole period in the drinking water, as well as in the hair samples. This paper demonstrates the potential use of laser ablation ICP-MS to provide measurements on a single hair strand and its potential to become a very powerful tool in hair analysis for biological monitoring.

  1. Analysis of non-equilibrium phenomena in inductively coupled plasma generators

    NASA Astrophysics Data System (ADS)

    Zhang, W.; Lani, A.; Panesi, M.

    2016-07-01

    This work addresses the modeling of non-equilibrium phenomena in inductively coupled plasma discharges. In the proposed computational model, the electromagnetic induction equation is solved together with the set of Navier-Stokes equations in order to compute the electromagnetic and flow fields, accounting for their mutual interaction. Semi-classical statistical thermodynamics is used to determine the plasma thermodynamic properties, while transport properties are obtained from kinetic principles, with the method of Chapman and Enskog. Particle ambipolar diffusive fluxes are found by solving the Stefan-Maxwell equations with a simple iterative method. Two physico-mathematical formulations are used to model the chemical reaction processes: (1) A Local Thermodynamics Equilibrium (LTE) formulation and (2) a thermo-chemical non-equilibrium (TCNEQ) formulation. In the TCNEQ model, thermal non-equilibrium between the translational energy mode of the gas and the vibrational energy mode of individual molecules is accounted for. The electronic states of the chemical species are assumed in equilibrium with the vibrational temperature, whereas the rotational energy mode is assumed to be equilibrated with translation. Three different physical models are used to account for the coupling of chemistry and energy transfer processes. Numerical simulations obtained with the LTE and TCNEQ formulations are used to characterize the extent of non-equilibrium of the flow inside the Plasmatron facility at the von Karman Institute. Each model was tested using different kinetic mechanisms to assess the sensitivity of the results to variations in the reaction parameters. A comparison of temperatures and composition profiles at the outlet of the torch demonstrates that the flow is in non-equilibrium for operating conditions characterized by pressures below 30 000 Pa, frequency 0.37 MHz, input power 80 kW, and mass flow 8 g/s.

  2. Investigation of a measure of robustness in inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Makonnen, Yoseif; Beauchemin, Diane

    2015-01-01

    In industrial/commercial settings where operators often have minimal expertise in inductively coupled plasma (ICP) mass spectrometry (MS), there is a prevalent need for a response factor indicating robust plasma conditions, which is analogous to the Mg II/Mg I ratio in ICP optical emission spectrometry (OES), whereby a Mg II/Mg I ratio of 10 constitutes robust conditions. While minimizing the oxide ratio usually corresponds to robust conditions, there is no specific target value that is widely accepted as indicating robust conditions. Furthermore, tuning for low oxide ratios does not necessarily guarantee minimal matrix effects, as they really address polyatomic interferences. From experiments, conducted in parallel for both MS and OES, there were some element pairs of similar mass and very different ionization potential that were exploited for such a purpose, the rationale being that, if these elements were ionized to the same extent, then that could be indicative of a robust plasma. The Be II/Li I intensity ratio was directly related to the Mg II/Mg I ratio in OES. Moreover, the 9Be+/7Li+ ratio was inversely related to the CeO+/Ce+ and LaO+/La+ oxide ratios in MS. The effects of different matrices (i.e. 0.01-0.1 M Na) were also investigated and compared to a conventional argon plasma optimized for maximum sensitivity. The suppression effect of these matrices was significantly reduced, if not eliminated in the case of 0.01 M Na, when the 9Be+/7Li+ ratio was around 0.30 on the Varian 820 MS instrument. Moreover, a very similar ratio (0.28) increased robustness to the same extent on a completely different ICP-MS instrument (PerkinElmer NEXION). Much greater robustness was achieved using a mixed-gas plasma with nitrogen in the outer gas and either nitrogen or hydrogen as a sheathing gas, as the 9Be+/7Li+ ratio was then around 1.70. To the best of our knowledge, this is the first report on using a simple analyte intensity ratio, 9Be+/7Li+, to gauge plasma robustness.

  3. Controlling the relative rates of adlayer formation and removal during etching in inductively coupled plasmas

    NASA Astrophysics Data System (ADS)

    Fuller, Nicholas Colvin Masi

    Laser desorption (LD) of the adlayer coupled with laser induced fluorescence (LIF) and plasma induced emission (PIE) of desorbed adsorbates is used to investigate the relative rates of chlorination and sputtering during the etching of Si in inductively coupled Cl2-Ar plasmas. Such an analysis is a two-fold process: surface analysis and plasma characterization. Surface analysis of Si etching using LD-LIF and LD-PIE techniques combined with etch rate measurements have revealed that the coverage of SiCl2 and etch rate increases and coverage of Si decreases abruptly for a chlorine fraction of 75% and ion energy of 80 eV. The precise Cl2 fraction for which these abrupt changes occur increases with an increase in ion energy. These changes may be caused by local chemisorption-induced reconstruction of Si <100>. Furthermore, the chlorination and sputtering rates are increased by ˜ an order of magnitude as the plasma is changed from Ar-dominant to Cl-dominant. Characterization of the plasma included determination of the dominant ion in Cl2 plasmas using LIF and a Langmuir probe and measurement of the absolute densities of Cl2, Cl, Cl+, and At + in Cl2-Ar discharges using optical emission actinometry. These studies reveal that Cl+ is the dominant positive ion in the H-mode and the dissociation of Cl2 to Cl increases with an increase in Ar fraction due to an increase in electron temperature. Furthermore, for powers exceeding 600 W, the neutral to ion flux ratio is strongly dependent on Cl2 fraction and is attributed mostly to the decrease in Cl density. Such dependence of the flux ratio on Cl2 fraction is significant in controlling chlorination and sputtering rates not only for Si etching, but for etching other key technological materials. ICP O2 discharges were also studied for low-kappa polymeric etch applications. These studies reveal that the electron temperature is weakly dependent on rf power and O2 dissociation is low (˜2%) at the maximum rf power density of 5.7 Wcm

  4. The 26th IEEE international conference on plasma science

    SciTech Connect

    1999-07-01

    Some of the sessions covered by this conference are: Basic Processes in Fully and Partially Ionized Plasmas; Slow Wave Devices; Laser-Produced Plasma; Non-Equilibrium Plasma Processing; Space Plasmas and Partially Ionized Gases; Microwave Plasmas; Inertial Confinement Fusion; Plasma Diagnostics; Computational Plasma Physics; Microwave Systems; Laser Produced Plasmas and Dense Plasma Focus; Intense Electron and Ion Beams; Fast Wave Devices; Spherical Configurations and Ball Lightning; Thermal Plasma Chemistry and Processing and Environmental Issues in Plasma Science; Plasma, Ion, and Electron Sources; Fast Wave Devices and Intense Beams; Fast Z-pinches and X-ray Lasers; Plasma Opening Switches; Plasma for Lighting; Intense Beams; Vacuum Microwaves; Magnetic Fusion Energy; and Plasma Thrusters and Arcs. Separate abstracts were prepared for some of the papers in this volume.

  5. Comparative Sulfur Analysis Using Thermal Combustion or Inductively Coupled Plasma Methodology and Mineral Composition of Common Livestock Feedstuffs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to compare the ability of thermal combustion (CNS) and inductively coupled plasma (ICP) to measure the total sulfur (S) content in plant-, animal-, and mineral-based feedstuffs commonly fed to livestock. Analyses of a wide range of feedstuffs by CNS and ICP for total ...

  6. HIGH RESOLUTION INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY ALLOWS RAPID ASSESSMENT OF IRON ABSORPTION IN INFANTS AND CHILDREN

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stable isotope absorption studies of iron have been limited by the high cost and limited availability of isotope ratio analysis using thermal ionization MS (TIMS). The development of high-resolution double focusing inductively coupled plasma MS (ICP-MS) may permit more cost-efficient sample analysis...

  7. Plasma Processes and Polymers: 16th International Symposium on Plasma Chemistry Taormina, Italy June 22-27, 2003

    NASA Astrophysics Data System (ADS)

    D'Agostino, Riccardo; Favia, Pietro; Oehr, Christian; Wertheimer, Michael R.

    2005-04-01

    This volume compiles essential contributions to the most innovative fields of Plasma Processes and Polymers. High-quality contributions cover the fields of plasma deposition, plasma treatment of polymers and other organic compounds, plasma processes under partial vacuum and at atmospheric pressure, biomedical, textile, automotive, and optical applications as well as surface treatment of bulk materials, clusters, particles and powders. This unique collection of refereed papers is based on the best contributions presented at the 16th International Symposium on Plasma Chemistry in Taormina, Italy (ISPC-16, June 2003). A high class reference of relevance to a large audience in plasma community as well as in the area of its industrial applications.

  8. Study of polymer ablation products obtained by ultraviolet laser ablation — inductively coupled plasma atomic emission spectrometry

    NASA Astrophysics Data System (ADS)

    Todolí, J.-L.; Mermet, J.-M.

    1998-10-01

    A study of the nature of aerosols following polymer laser ablation was performed. A glass sample was used for comparison. Aerosol fractions were analyzed by using simple methods based on transport efficiency and filters. Three different tube lengths, i.e. 4, 29 and 54 m, were inserted between the ablation cell and the inductively coupled plasma atomic emission spectrometry (ICP-AES) injector. For the glass sample, 10 elements were studied. Only Na and K exhibited different results as the particle size, i.e. tube length, was varied. The polymers used were poly(vinyl chloride), PVC, and poly(ethylene), PE. Three elements (Ca, Ti and Sn) under different chemical forms were measured. Unlike Ti and Sn the ablated aerosol particle size (mass) seemed to depend on the Ca chemical form. Another PVC sample containing 11 elements was also studied. Na, Al and C exhibited a different behavior with particle size with respect to the remaining elements. Then, the carbon signal was studied after a 0.3 μm pore size filter had been placed between the ablation cell and the ICP torch. The results indicated that carbon was mainly present under gaseous form and particles smaller than 0.3 μm size. The analysis of the aerosol gaseous phase by thermal desorption GC-MS confirmed the presence of polymer volatile thermal degradation products. These results explained why carbon could not be applied as an efficient internal standard.

  9. Direct multielement trace analyses of silicon carbide powders by spark ablation simultaneous inductively coupled plasma optical emission spectrometry

    NASA Astrophysics Data System (ADS)

    Kiera, Arne F.; Schmidt-Lehr, Sebastian; Song, Ming; Bings, Nicolas H.; Broekaert, José A. C.

    2008-02-01

    A procedure for the direct analysis of silicon carbide powders (SiC) by simultaneous detection inductively coupled plasma optical emission spectrometry using a Spectro-CIROS™ spectrometer (CCD-ICP-OES) and a novel spark ablation system Spectro-SASSy (SA) as sample introduction technique is described. The sample preparation procedure for SA of non-conducting material is based on mixing the sample powders with a conducting matrix, in this case copper and briquetting pellets. Pressing time, pressure and mixing ratio are shown to be important parameters of the pelleting technique with respect to their mechanical stability for the reliability of the analysis results. A mixing ratio of 0.2 g +0.6 g for SiC and Cu, a pressure of 10 t cm - 2 and a pressing time of 8 min have been found optimum. It has also been shown that the spark parameters selected are crucial for uniform volatilization. Electron probe micrographs of the burning spots and the analytical signal magnitude showed that a rather hard spark at 100 Hz was optimum. The determination of trace elements in silicon carbide powders is demonstrated using a calibration based on the addition of standard solutions. For Al, Ti, V, Mn and Fe detection limits in the lower µg g - 1 range can be achieved. Internal standardization with Y in combination with the addition of standard solutions allows relative standard deviations in the range of 4 to 24% for concentration levels of the order of 3 to 350 µg g - 1 .

  10. Inductively coupled plasma-mass spectrometric method for the determination of dissolved trace elements in natural water

    USGS Publications Warehouse

    Garbarino, J.R.; Taylor, Howard E.

    1996-01-01

    An inductively coupled plasma-mass spectrometry method was developed for the determination of dissolved Al, As, B, Ba, Be, Cd, Co, Cr, Cu, Li, Mn, Mo, Ni, Pb, Sr, Tl, U, V, and Zn in natural waters. Detection limits are generally in the 50-100 picogram per milliliter (pg/mL) range, with the exception of As which is in the 1 microgram per liter (ug/L) range. Interferences associated with spectral overlap from concomitant isotopes or molecular ions and sample matrix composition have been identified. Procedures for interference correction and reduction related to isotope selection, instrumental operating conditions, and mathematical data processing techniques are described. Internal standards are used to minimize instrumental drift. The average analytical precision attainable for 5 times the detection limit is about 16 percent. The accuracy of the method was tested using a series of U.S. Geological Survey Standard Reference Water Standards (SWRS), National Research Council Canada Riverine Water Standard, and National Institute of Standards and Technology (NIST) Trace Elements in Water Standards. Average accuracies range from 90 to 110 percent of the published mean values.

  11. Influence of sample matrix components on the selection of calibration strategies in electrothermal vaporization inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Fonseca, R. W.; Miller-Ihli, N. J.

    1996-11-01

    Quantification of both digested and slurry samples were studied using ultrasonic slurry electrothermal vaporization inductively coupled plasma mass spectrometry (USS-ETV-ICP-MS). The results of external calibration using aqueous standards, method of additions, and In as an internal standard were compared. The elements studied include: Mn, Ni and Cu and the materials analyzed include: NIST SRM 1548 total diet and SRM 1549 milk powder. Palladium was used as a physical carrier and oxygen ashing was used to remove the organic part of the slurry matrix. Different degrees of matrix suppression effects were observed when different skimmer cones were employed. Aging of the skimmer cone and consequent loss of its original circular symmetry and decrease in orifice size resulted in differences in sampling of the ion beam and changes in the degree of matrix effects were observed as the skimmer cone was rotated. The presence of matrix suppression effects is evidenced by strong suppressions in the Ar 2, C and analyte signals. When matrix suppression effects were present, the method of external calibration provided low recoveries (average accuracy 73 ± 12%), therefore it was necessary to use the method of additions to compensate for these problems, providing an average accuracy of 108 ± 13%. When matrix effects were absent, the external calibration method resulted in an average accuracy of 101 ± 16%.

  12. Provenance determination of oriental porcelain using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS).

    PubMed

    Bartle, Emma K; Watling, R John

    2007-03-01

    The sale of fraudulent oriental ceramics constitutes a large proportion of the illegal artifact and antique trade and threatens to undermine the legitimate international market. The sophistication and skill of forgers has reached a level where, using traditional appraisal by eye and hand, even the most experienced specialist is often unable to distinguish between a genuine and fraudulent piece. In addition, current provenancing techniques such as energy-dispersive X-ray fluorescence (EDXRF) spectrometry and thermoluminescence (TL) dating can result in significant damage to the artifact itself. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), a relatively nondestructive analytical technique, has been used for the provenance determination of materials based on geographical origin. The technique requires the production of a laser crater, c. 100 microm in diameter, which is essentially invisible to the naked eye. Debris from this crater is analyzed using ICP-MS, with the results forming the basis of the provenance establishment protocol. Chinese, Japanese, and English porcelain shards have been analyzed using this protocol and generic isotopic distribution patterns have been produced that enable the provenance establishment of porcelain artifacts to their country of production. Minor variations between elemental fingerprints of artifacts produced in the same country also indicate that it may be possible to further provenance oriental ceramics to a specific production region or kiln site. PMID:17316230

  13. Evaluation of the mineral profile of textile materials using inductively coupled plasma optical emission spectrometry and chemometrics.

    PubMed

    Menezes, E A; Carapelli, R; Bianchi, S R; Souza, S N P; Matos, W O; Pereira-Filho, E R; Nogueira, A R A

    2010-10-15

    The content of Al, Ba, Ca, Cr, Cu, Fe, Ni, P, Zn, Cd and Pb was determined in textile material samples after microwave-assisted decomposition in a cavity oven and extraction with an artificial sweat solution. Radial viewing inductively coupled plasma optical emission spectrometry (ICP OES) was the main detection technique, but Cd and Pb were determined by thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS) to increase the sensitivity. Principal components analysis (PCA) was applied to the data sets to characterize the samples with respect to their geographic origin and color difference. The PCA for Brazilian single-color samples showed separation, with one group consisting of blue and green textiles and another with all the other materials evaluated. The geographic origin study showed a clear separation between Brazilian and Chinese textiles. The metals amount extracted with sweat extractable solution were lower than limits values pointed by the International Testing and Certification System for Textiles, Oko Tex Standard 100, in the all considered classes. Recoveries varied from 85 to 112% for additions ranging from 3.0 to 25 mg kg(-1) for Ca and from 0.3 to 7.0 mg kg(-1) for all other analytes through the microwave-assisted decomposition procedure. PMID:20599322

  14. Development and validation of an inductively coupled plasma mass spectrometry method for quantification of levothyroxine in dissolution studies.

    PubMed

    Pabla, Dimple; Akhlaghi, Fatemeh; Ahmed, Aftab; Zia, Hossein

    2008-04-01

    A simple, sensitive and reproducible inductively coupled plasma mass spectrometry (ICP-MS) method for the direct determination of levothyroxine (T4), based on the analysis of iodide content, in aqueous media was developed. The sample preparation consisted of addition of antimony, as the internal standard, and dilution with a 0.5% ammonia solution. The analytes were quantified at m/z 126.90 and 120.90 for iodide and antimony, respectively. The assay was linear in the concentration range of 0.1-50 ng/mL for iodide and 0.3-100 ng/mL for T4. The method was precise and accurate with lower limits of quantification (LLOQs) of 0.1 ng/mL for iodide and 0.3 ng/mL for T4. The inter-day accuracy was >94% for both analytes and the coefficient of variation (%CV) was less than 5%. The method has successfully been used for dissolution studies of T4 formulations and holds immense promise as a simple, precise and sensitive analytical technique for T4 concentration determination in in vitro studies. PMID:18320549

  15. Analysis of Mineral and Heavy Metal Content of Some Commercial Fruit Juices by Inductively Coupled Plasma Mass Spectrometry

    PubMed Central

    Dehelean, Adriana; Magdas, Dana Alina

    2013-01-01

    The presence of potentially toxic elements and compounds in foodstuffs is of intense public interest and thus requires rapid and accurate methods to determine the levels of these contaminants. Inductively coupled plasma mass spectrometry is a powerful tool for the determination of metals and nonmetals in fruit juices. In this study, 21 commercial fruit juices (apple, peach, apricot, orange, kiwi, pear, pineapple, and multifruit) present on Romanian market were investigated from the heavy metals and mineral content point of view by ICP-MS. Our obtained results were compared with those reported in literature and also with the maximum admissible limit in drinking water by USEPA and WHO. For Mn the obtained values exceeded the limits imposed by these international organizations. Co, Cu, Zn, As, and Cd concentrations were below the acceptable limit for drinking water for all samples while the concentrations of Ni and Pb exceeded the limits imposed by USEPA and WHO for some fruit juices. The results obtained in this study are comparable to those found in the literature. PMID:24453811

  16. Analysis of mineral and heavy metal content of some commercial fruit juices by inductively coupled plasma mass spectrometry.

    PubMed

    Dehelean, Adriana; Magdas, Dana Alina

    2013-01-01

    The presence of potentially toxic elements and compounds in foodstuffs is of intense public interest and thus requires rapid and accurate methods to determine the levels of these contaminants. Inductively coupled plasma mass spectrometry is a powerful tool for the determination of metals and nonmetals in fruit juices. In this study, 21 commercial fruit juices (apple, peach, apricot, orange, kiwi, pear, pineapple, and multifruit) present on Romanian market were investigated from the heavy metals and mineral content point of view by ICP-MS. Our obtained results were compared with those reported in literature and also with the maximum admissible limit in drinking water by USEPA and WHO. For Mn the obtained values exceeded the limits imposed by these international organizations. Co, Cu, Zn, As, and Cd concentrations were below the acceptable limit for drinking water for all samples while the concentrations of Ni and Pb exceeded the limits imposed by USEPA and WHO for some fruit juices. The results obtained in this study are comparable to those found in the literature. PMID:24453811

  17. Rapid and sensitive determination of tellurium in soil and plant samples by sector-field inductively coupled plasma mass spectrometry.

    PubMed

    Yang, Guosheng; Zheng, Jian; Tagami, Keiko; Uchida, Shigeo

    2013-11-15

    In this work, we report a rapid and highly sensitive analytical method for the determination of tellurium in soil and plant samples using sector field inductively coupled plasma mass spectrometry (SF-ICP-MS). Soil and plant samples were digested using Aqua regia. After appropriate dilution, Te in soil and plant samples was directly analyzed without any separation and preconcentration. This simple sample preparation approach avoided to a maximum extent any contamination and loss of Te prior to the analysis. The developed analytical method was validated by the analysis of soil/sediment and plant reference materials. Satisfactory detection limits of 0.17 ng g(-1) for soil and 0.02 ng g(-1) for plant samples were achieved, which meant that the developed method was applicable to studying the soil-to-plant transfer factor of Te. Our work represents for the first time that data on the soil-to-plant transfer factor of Te were obtained for Japanese samples which can be used for the estimation of internal radiation dose of radioactive tellurium due to the Fukushima Daiichi Nuclear Power Plant accident. PMID:24148390

  18. A rugged and transferable method for determining blood cadmium, mercury, and lead with inductively coupled plasma-mass spectrometry

    NASA Astrophysics Data System (ADS)

    McShane, William J.; Pappas, R. Steven; Wilson-McElprang, Veronica; Paschal, Dan

    2008-06-01

    A simple, high-throughput method for determining total cadmium, mercury, and lead in blood in cases of suspected exposure, using inductively coupled plasma-mass spectrometry (ICP-MS), has been developed and validated. One part matrix-matched standards, blanks, or aliquots of blood specimens were diluted with 49 parts of a solution containing 0.25% (w/w) tetramethylammonium hydroxide; 0.05% v/v Triton X-100 (blood cell membranes and protein solubilization); 0.01% (w/v) ammonium pyrolidinedithiocarbamate (mercury memory effect prevention and oxidation state stabilization, solubilization by complexation of all three metals); 1% v/v isopropanol (signal enhancement); and 10 μg/L iridium (internal standard). Thus the final dilution factor is 1 + 49. The method provides the basis for the determination of total cadmium, mercury, and lead for assessment of environmental, occupational, accidental ingestion or elevated exposures from other means. Approximately 80 specimens, including blanks, calibration standards, and quality control materials can be processed in an 8-h day. The method has been evaluated by examining reference materials from the National Institute of Standards and Technology, as well as by participation in six rounds of proficiency testing intercomparisons led by the Wadsworth Center of the New York State Department of Health. This method was developed for the purpose of increasing U.S. emergency response laboratory capacity. To this end, 33 U.S. state, and 1 district health department laboratories have validated this method in their own laboratories.

  19. Multielemental inductively coupled plasma optical emission spectrometry analysis of nickeliferous minerals.

    PubMed

    Abad-Peña, Elizabet; Larrea-Marín, María Teresa; Villanueva-Tagle, Margarita Edelia; Pomares-Alfonso, Mario Simeón

    2014-06-01

    An inductively coupled plasma optical emission spectrometry method for the quantitative simultaneous determination of Al, Ca, Co, Cu, Cr, Fe, K, Mg, Mn, Na, Ni, P and Zn in Cuban laterite and serpentine minerals has been developed. Additionally, V and Ti can be quantitatively determined in laterite mineral; Li, Sr, and Zr can be detected in both mineral types and Pb can be detected just in laterite mineral. The microwave-assisted total acid digestion of samples was achieved with HCl+HNO3+HF and HNO3+HClO4+HF acid mixtures for laterite and serpentine samples, respectively. In non-robust plasma operating conditions, the matrix effect characteristics of the laterite sample were dictated by the principal component Fe; while the character of the Mg principal component matrix effect was some how modified by the concomitants Fe and Ni in serpentine sample. The selection of robust conditions decreased the matrix effect. Additionally, the simulation of the matrix samples by introducing the principal component Fe or Mg, correspondingly, in calibration dissolutions was needed to overcome completely the matrix effect over the analysis accuracy. Precision of analysis was very near or lower than 10% for most elements, except Sr (15%) in L-1; and K (15%) and Li (15%) in SNi sample. Accuracy of analysis was around or lowers than 10% for most elements, except K (15%), Na (19%), P (19%) and V (19%) in L-1 sample; and Ca (14%) and P (20%) in SNi sample. PMID:24767449

  20. Electromagnetic wave attenuation measurements in a ring-shaped inductively coupled air plasma

    NASA Astrophysics Data System (ADS)

    Wei, Xiaolong; Xu, Haojun; Li, Jianhai; Lin, Min; Su; Chen

    2015-05-01

    An aerocraft with the surface, inlet and radome covered large-area inductive coupled plasma (ICP) can attenuate its radar echo effectively. The shape, thickness, and electron density ( N e ) distribution of ICP are critical to electromagnetic wave attenuation. In the paper, an air all-quartz ICP generator in size of 20 × 20 × 7 cm3 without magnetic confinement is designed. The discharge results show that the ICP is amorphous in E-mode and ring-shaped in H-mode. The structure of ICP stratifies into core region and edge halo in H-mode, and its width and thickness changes from power and pressure. Such phenomena are explained by the distribution of RF magnetic field, the diffusion of negative ions plasma and the variation of skin depth. In addition, the theoretical analysis shows that the N e achieves nearly uniform within the electronegative core and sharply steepens in the edge. The N e of core region is diagnosed by microwave interferometer under varied conditions (pressure in range of 10-50 Pa, power in 300-700 W). Furthermore, the electromagnetic wave attenuation measurements were carried out with the air ICP in the frequencies of 4-5 GHz. The results show that the interspaced ICP is still effective to wave attenuation, and the wave attenuation increases with the power and pressure. The measured attenuation is approximately in accordance with the calculation data of finite-different time-domain simulations.

  1. Pulsed, Inductively Generated, Streaming Plasma Ion Source for Heavy Ion Fusion Linacs

    SciTech Connect

    Steven C. Glidden; Howard D Sanders; John B. Greenly; Daniel L. Dongwoo

    2006-04-28

    This report describes a compact, high current density, pulsed ion source, based on electrodeless, inductively driven gas breakdown, developed to meet the requirements on normalized emittance, current density, uniformity and pulse duration for an ion injector in a heavy-ion fusion driver. The plasma source produces >10 μs pulse of Argon plasma with ion current densities >100 mA/cm2 at 30 cm from the source and with strongly axially directed ion energy of about 80 eV, and sub-eV transverse temperature. The source has good reproducibility and spatial uniformity. Control of the current density during the pulse has been demonstrated with a novel modulator coil method which allows attenuation of the ion current density without significantly affecting the beam quality. This project was carried out in two phases. Phase 1 used source configurations adapted from light ion sources to demonstrate the feasibility of the concept. In Phase 2 the performance of the source was enhanced and quantified in greater detail, a modulator for controlling the pulse shape was developed, and experiments were conducted with the ions accelerated to >40 kV.

  2. Ion Energy Distributions and their Relative Abundance in Inductively Coupled Plasmas

    NASA Technical Reports Server (NTRS)

    Kim, J. S.; Rao, M. V. V. S.; Cappelli, M. A.; Sharma, S. P.; Arnold, James O. (Technical Monitor)

    1998-01-01

    Study of kinetics of ions and neutrals produced in high density inductively coupled plasma (ICP) discharges is of great importance for achieving a high degree of plasma assisted deposition and etching. In this paper, we present the ion energy distributions (IEDs) of various ions arriving at the grounded lower electrode. The ions were energy as well as mass analyzed by a combination of electrostatic analyzer-quadrupole mass spectrometer for pure Ar and CF4/Ar mixtures. The measurements have been made at gas pressures ranging from 30 to 100 mTorr. In addition, the IEDs were measured when the wafer-supporting electrode was also rf-powered and the effect of the self-bias was observed in the energy distributions of ions. The shapes of the IEDs are discussed an related to the sheath properties and measured electrical waveforms, as a function of pressure and applied power. Relative ion intensities were obtained by integration of each ion kinetic energy distribution function over its energy range.

  3. Controlling VUV photon fluxes in low-pressure inductively coupled plasmas

    NASA Astrophysics Data System (ADS)

    Tian, Peng; Kushner, Mark J.

    2015-06-01

    Low-pressure (a few to hundreds of millitorrs) inductively coupled plasmas (ICPs), as typically used in microelectronics fabrication, often produce vacuum-ultraviolet (VUV) photon fluxes onto surfaces comparable to or exceeding the magnitude of ion fluxes. These VUV photon fluxes are desirable in applications such as sterilization of medical equipment but are unwanted in many materials fabrication processes due to damage to the devices by the high-energy photons. Under specific conditions, VUV fluxes may stimulate etching or synergistically combine with ion fluxes to modify polymeric materials. In this regard, it is desirable to control the magnitude of VUV fluxes or the ratio of VUV fluxes to those of other reactive species, such as ions, or to discretely control the VUV spectrum. In this paper, we discuss results from a computational investigation of VUV fluxes from low-pressure ICPs sustained in rare gas mixtures. The control of VUV fluxes through the use of pressure, pulsed power, and gas mixture is discussed. We found that the ratio, β, of VUV photon to ion fluxes onto surfaces generally increases with increasing pressure. When using pulsed plasmas, the instantaneous value of β can vary by a factor of 4 or more during the pulse cycle due to the VUV flux more closely following the pulsed power.

  4. Inductively coupled plasma mass spectrometry applied to isotopic analysis of iron in human fecal matter

    SciTech Connect

    Ting, B.T.G.; Janghorbani, M.

    1986-06-01

    Inductively coupled plasma mass spectrometry combined with stable isotope dilution is applied to accurate isotopic analysis of human fecal matter for /sup 54/Fe and /sup 58/Fe. Argon plasma generated interferences are of minor concern. The interference from /sup 54/Cr can be corrected instrumentally, whereas /sup 58/Ni must be removed chemically. The ratio of the stable isotopes of interest can be measured routinely with a relative standard deviation of about 1%. The overall accuracy of the method for quantitative isotopic analyses is evaluated in Standard Reference Material (SRM) 1577a (Bovine Liver), fecal homogenate subsamples, and synthetic solutions of iron. For SRM 1577a, the respective comparisons are (..mu..g/g) 192.2 +/- 2.2 (present method) vs. 194 +/- 20 (certified value). For the fecal matrix, the present method yields (..mu..g/mL) 15.14 +/- 0.36 vs. 15.82 +/- 0.48 based on atomic absorption spectrophotometry. For an iron solution (250 ppm), replicate analyses yield the value of 245.4 +/- 1.5 ppm.

  5. Some Temperature Effects on AISI-304 Nitriding in an Inductively Coupled RF Plasma

    SciTech Connect

    Valencia-Alvarado, R.; Barocio, S. R.; Mercado-Cabrera, A.; Pena-Eguiluz, R.; Munoz-Castro, A. E.; Piedad-Beneitez, A. de la; Rosa-Vazquez, J. de la; Lopez-Callejas, R.; Godoy-Cabrera, O. G.

    2006-12-04

    Some recent results obtained from nitriding AISI 304 stainless steel samples, 1.2 cm in diameter and 0.5 cm thick are reported here in the case of an 85% hydrogen and 15% nitrogen mixture work gas. The process was carried out from 300 to 400 W for (13.56 MHz) inductively coupled plasma within a 60 cm long pyrex glass tube 3.5 cm in diameter where the samples were biased up to -300 V with respect to earth. The resulting hardness appears to be a function of the substrate temperature which varied from 200 deg. C at a 0 V bias to 550 deg. C at -300 V. The plasma density at 400 W reached 3x1010 cm-3 with a 4 eV electron temperature. Prior to nitriding, all the samples were polished with 0.05 {mu}m diamond paste, leading to a 30 nm average roughness (Ra). After nitriding at -300 V, the Ra rose until {approx}400 nm while hardness values of 1500 HV under 300 g loads were measured. X ray diffraction indicates that the extended phase amplitude ({gamma}N), Fe and Cr nitride depends on the substrate temperature.

  6. Preparation of Nanocomposite GDC/LSCF Cathode Material for IT-SOFC by Induction Plasma Spraying

    NASA Astrophysics Data System (ADS)

    Shen, Yan; Almeida, Veronica Alexandra B.; Gitzhofer, François

    2011-01-01

    Homogeneous mixtures of Ce0.8Gd0.2O1.9 (GDC) and La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) nanopowders were successfully synthesized using induction plasma by axial injection of a solution. The resulting nanocomposite powders consisted of two kinds of nanopowders with different mass ratio of GDC/LSCF, such as 3/7 and 6/4. The morphological features, crystallinity, and the phases of the synthesized powders were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), local energy-dispersive x-ray spectroscopy (EDS) analysis, and x-ray diffraction (XRD). The nanopowders are almost globular in shape with a diameter smaller than 100 nm and their BET specific areas are around 20 m2 g-1. The GDC and LSCF phases are well distributed in the nanopowders. In addition, suspensions, made with the as-synthesized composite nanopowders and ethanol, were used to deposit cathode coatings using suspension plasma spray (SPS). Micro-nanostructures of the coatings are discussed. The coatings are homogeneous and porous (51% porosity) with cauliflower structures.

  7. Ion Clouds in the Inductively Coupled Plasma Torch: A Closer Look through Computations.

    PubMed

    Aghaei, Maryam; Lindner, Helmut; Bogaerts, Annemie

    2016-08-16

    We have computationally investigated the introduction of copper elemental particles in an inductively coupled plasma torch connected to a sampling cone, including for the first time the ionization of the sample. The sample is inserted as liquid particles, which are followed inside the entire torch, i.e., from the injector inlet up to the ionization and reaching the sampler. The spatial position of the ion clouds inside the torch as well as detailed information on the copper species fluxes at the position of the sampler orifice and the exhausts of the torch are provided. The effect of on- and off-axis injection is studied. We clearly show that the ion clouds of on-axis injected material are located closer to the sampler with less radial diffusion. This guarantees a higher transport efficiency through the sampler cone. Moreover, our model reveals the optimum ranges of applied power and flow rates, which ensure the proper position of ion clouds inside the torch, i.e., close enough to the sampler to increase the fraction that can enter the mass spectrometer and with minimum loss of material toward the exhausts as well as a sufficiently high plasma temperature for efficient ionization. PMID:27457191

  8. Acid retardation method in analysis of strongly acidic solutions by inductively coupled plasma mass-spectrometry.

    PubMed

    Seregina, I F; Perevoznik, O A; Bolshov, M A

    2016-10-01

    Acid retardation on the sorbents as a technique for reduction of the acidity of the solutions prior to their analysis by inductively coupled plasma mass spectrometry was proposed and investigated. The proposed scheme provides substantial separation of the analytes and nitric acid, which allows direct introduction of the eluates in plasma without dilution. Two sorbents were examined - AV-17 anion-exchange resin and the Stirosorb 584 sorbent. Sorption and desorption of 38 elements on these sorbents were investigated. The efficiencies of the REEs' sorption on the anion-exchange and neutral sorbents were compared. The higher efficiency of the REEs and HNO3 separation was revealed for the neutral Stirosorb 584 sorbent. It was also found that most elements come out quantitatively of the column filled with the AV-17 resin after pumping 2-4mL of the solution. Wherein, the concentration of nitric acid decreased by 20 times. The anomalous behaviour of Ag, Pb, Th and U on the AV-17 resin was found. These analytes were eluted only after pumping 4 column volumes of deionized water. Na, K, Fe, Al and Li in concentrations within (50-1000mgL(-1)) range did not affect the recovery of REEs. The potential of ARM technique was demonstrate by the analysis of puriss. HNO3 and silverware. ARM enables to avoid dilution of highly acidic solutions prior to their introduction in ICP-MS. PMID:27474322

  9. The Kalman filter approach to inductively coupled plasma atomic emission spectrometry

    NASA Astrophysics Data System (ADS)

    Van Veen, E. H.; Bosch, S.; De Loos-Vollebregt, M. T. C.

    1994-07-01

    This article is an electronic publication in Spectrochimica Acta Electronica (SAE), the electronic section of Spectrochimica Acta Part B (SAB). The hardcopy text, comprising the main article and two appendices, is accompanied by a disk containing the compiled program, a reference manual and data files. The work deals with data handling in inductively coupled plasma atomic emission spectrometry (ICP-AES). With this technique, the analyte signal is superimposed on a background signal. When separating the signals by manual or automated three-point background correction, there are many instances in which the data reduction fails. Based on scans recorded in a fast-scanning mode and on a library of pure-component scans, the Kaiman filter approach models the emission in the spectral window (about 100 pm) of the analyte and mathematically solves the problem of background correction. By using a criterion-based algorithm to correct for optical instability, the uncertainty in the determination of the interferent line signal is eliminated. Therefore, the present filter implementation yields more accurate and precise results, especially in the case of line overlap. The Kalman filter Approach to Atomic Spectrometry (KAAS) software automatically processes Perkin-Elmer Plasma 1000/2000 text files, but can also handle ASCII data files. Practical and comprehensive examples are given to evoke the "Kalman filter feeling" in the crucial step of creating the emission model.

  10. Numerical Investigation of Flow Fields in Inductively Coupled Plasma Wind Tunnels

    NASA Astrophysics Data System (ADS)

    Yu, Minghao; Yusuke, Takahashi; Hisashi, Kihara; Ken-ichi, Abe; Kazuhiko, Yamada; Takashi, Abe

    2014-10-01

    Numerical simulations of 10 kW and 110 kW inductively coupled plasma (ICP) wind tunnels were carried out to study physical properties of the flow inside the ICP torch and vacuum chamber with air as the working gas. Two-dimensional compressible axisymmetric Navier-Stokes (N-S) equations that took into account 11 species and 49 chemical reactions of air, were solved. A heat source model was used to describe the heating phenomenon instead of solving the electromagnetic equations. In the vacuum chamber, a four-temperature model was coupled with N-S equations. Numerical results for the 10 kW ICP wind tunnel are presented and discussed in detail as a representative case. It was found that the plasma flow in the vacuum chamber tended to be in local thermochemical equilibrium. To study the influence of operation conditions on the flow field, simulations were carried out for different chamber pressures and/or input powers. The computational results for the above two ICP wind tunnels were compared with corresponding experimental data. The computational and experimental results agree well, therefore the flow fields of ICP wind tunnels can be clearly understood.

  11. Investigations of the use of inductively coupled plasma emissions for chemical analysis

    NASA Astrophysics Data System (ADS)

    Heine, D. R.

    Investigations of applications of the inductively coupled plasma (ICP) for analytical atomic emission spectroscopy are performed. Emissions below 185 nm, analysis of wear metals in lubricating oils, and use of the ICP as a selective detector for high performance liquid chromatography (HPLC) are studied. A unique plasma coolant tube containing a side arm which allows direct observation of the discharge is used to investigate emissions in the vacuum ultraviolet spectral region between 120 and 185 nm. Emission from elements which do not emit radiation in the visible region are observed. A heated sample introduction system attached to a Babington nebulizer is investigated as a means to aerosolize lubricating oils for introduction into the ICP. This allows direct analysis of wear metals in oil samples without requiring the usual sample dilutions. The ICP is used as a selective detector for HPLC. Nucleotides separated by anion exchange chromatography are determined in the ICP by observing phosphorous emissions. Methanol and acetonitrile used for reverse phase HPLC are successfully run in the IPC.

  12. Neutral Gas Temperature Estimates in an Inductively Coupled CF4 Plasma by Fitting Diatomic Emission Spectra

    NASA Technical Reports Server (NTRS)

    Cruden, Brett A.; Rao, M. V. V. S.; Sharma, Surendra P.; Meyyappan, M.

    2001-01-01

    This work examines the accuracy of plasma neutral temperature estimates by fitting the rotational band envelope of different diatomic species in emission. Experiments are performed in an inductively coupled CF4 plasma generated in a Gaseous Electronics Conference reference cell. Visible and ultraviolet emission spectra are collected at a power of 300 W (approximately 0.7 W/cc) and pressure of 30 mtorr. The emission bands of several molecules (CF, CN, C2, CO, and SiF) are fit simultaneously for rotational and vibrational temperatures and compared. Four different rotational temperatures are obtained: 1250 K for CF and CN, 1600 K for CO, 1800 K for C2, and 2300 K for SiF. The vibrational temperatures obtained vary from 1750-5950 K, with the higher vibrational temperatures generally corresponding to the lower rotational temperatures. These results suggest that the different species have achieved different degrees of equilibration between the rotational and vibrational modes and may not be equilibrated with the translational temperatures. The different temperatures are also related to the likelihood that the species are produced by ion bombardment of the surface, with etch products like SiF, CO, and C2 having higher temperatures than species expected to have formed in the gas phase.

  13. Modeling of inductively coupled plasma SF{sub 6}/O{sub 2}/Ar plasma discharge: Effect of O{sub 2} on the plasma kinetic properties

    SciTech Connect

    Pateau, Amand; Rhallabi, Ahmed Fernandez, Marie-Claude; Boufnichel, Mohamed; Roqueta, Fabrice

    2014-03-15

    A global model has been developed for low-pressure, inductively coupled plasma (ICP) SF{sub 6}/O{sub 2}/Ar mixtures. This model is based on a set of mass balance equations for all the considered species, coupled with the discharge power balance equation and the charge neutrality condition. The present study is an extension of the kinetic global model previously developed for SF{sub 6}/Ar ICP plasma discharges [Lallement et al., Plasma Sources Sci. Technol. 18, 025001 (2009)]. It is focused on the study of the impact of the O{sub 2} addition to the SF{sub 6}/Ar gas mixture on the plasma kinetic properties. The simulation results show that the electron density increases with the %O{sub 2}, which is due to the decrease of the plasma electronegativity, while the electron temperature is almost constant in our pressure range. The density evolutions of atomic fluorine and oxygen versus %O{sub 2} have been analyzed. Those atomic radicals play an important role in the silicon etching process. The atomic fluorine density increases from 0 up to 40% O{sub 2} where it reaches a maximum. This is due to the enhancement of the SF{sub 6} dissociation processes and the production of fluorine through the reactions between SF{sub x} and O. This trend is experimentally confirmed. On the other hand, the simulation results show that O(3p) is the preponderant atomic oxygen. Its density increases with %O{sub 2} until reaching a maximum at almost 40% O{sub 2}. Over this value, its diminution with O{sub 2}% can be justified by the high increase in the loss frequency of O(3p) by electronic impact in comparison to its production frequency by electronic impact with O{sub 2}.

  14. Homogeneous and Heterogeneous Reaction Mechanisms in CH3F-O2 Inductively Coupled Plasmas

    NASA Astrophysics Data System (ADS)

    Donnelly, Vincent M.; Karakas, Erdinc; Kaler, Sanbir; Lou, Qiaowei; Economou, Demetre J.

    2013-09-01

    CH3F/O2 containing plasmas are used in selective Si3N4 etching over Si or SiO2. Fundamental plasma studies in these gas mixtures are scarce. In this work, optical emission rare gas actinometry and a global chemistry model were employed to study inductively couple plasmas in CH3F/O2 gas mixtures. For constant CH3F and O2 flow rates, the absolute H, F and O atom densities increased linearly with power. The feedstock gas was highly dissociated and most of the fluorine and oxygen was contained in reaction products HF, CO, CO2, H2O and OH. Measured number densities as a function of O2 addition to CH3F/O2 changed abruptly for H, O, and particularly F atoms (factor of 4) at 48% O2 A corresponding transition was also observed in electron density, electron temperature and gas temperature, as well as in C, CF and CH optical emission. These abrupt transitions were attributed to the reactor wall reactivity, changing from a polymer-coated surface to a polymer-free surface, and vice-versa, as the O2 content in the feed gas crossed 48%. Homogeneous chemistry dominates above 48% O2; a kinetic model with no adjustable parameters is in excellent agreement with the absolute F and H and relative HF number density dependence on power and pressure. CH3F/O2 containing plasmas are used in selective Si3N4 etching over Si or SiO2. Fundamental plasma studies in these gas mixtures are scarce. In this work, optical emission rare gas actinometry and a global chemistry model were employed to study inductively couple plasmas in CH3F/O2 gas mixtures. For constant CH3F and O2 flow rates, the absolute H, F and O atom densities increased linearly with power. The feedstock gas was highly dissociated and most of the fluorine and oxygen was contained in reaction products HF, CO, CO2, H2O and OH. Measured number densities as a function of O2 addition to CH3F/O2 changed abruptly for H, O, and particularly F atoms (factor of 4) at 48% O2 A corresponding transition was also observed in electron density

  15. Computational Validation of a Two-Dimensional Semi-Empirical Model for Inductive Coupling in a Conical Pulsed Inductive Plasma Thruster

    NASA Technical Reports Server (NTRS)

    Hallock, Ashley K.; Polzin, Kurt A.

    2011-01-01

    A two-dimensional semi-empirical model of pulsed inductive thrust efficiency is developed to predict the effect of such a geometry on thrust efficiency. The model includes electromagnetic and gas-dynamic forces but excludes energy conversion from radial motion to axial motion, with the intention of characterizing thrust efficiency loss mechanisms that result from a conical versus a at inductive coil geometry. The range of conical pulsed inductive thruster geometries to which this model can be applied is explored with the use of finite element analysis. A semi-empirical relation for inductance as a function of current sheet radial and axial position is the limiting feature of the model, restricting the applicability as a function of half cone angle to a range from ten degrees to about 60 degrees. The model is nondimensionalized, yielding a set of dimensionless performance scaling parameters. Results of the model indicate that radial current sheet motion changes the axial dynamic impedance parameter at which thrust efficiency is maximized. This shift indicates that when radial current sheet motion is permitted in the model longer characteristic circuit timescales are more efficient, which can be attributed to a lower current sheet axial velocity as the plasma more rapidly decouples from the coil through radial motion. Thrust efficiency is shown to increase monotonically for decreasing values of the radial dynamic impedance parameter. This trend indicates that to maximize the radial decoupling timescale should be long compared to the characteristic circuit timescale.

  16. Determination of ammonium and organic bound nitrogen by inductively coupled plasma emission spectroscopy.

    PubMed

    Jaber, A M Y; Mehanna, N A; Sultan, S M

    2009-06-15

    The continuous flow sample introduction technique with a hydride generator system in conjunction with an inductively coupled plasma emission spectrometer (ICP-AES-HG), is used in this study for quantitative determination of ammonium and organic bound nitrogen in aqueous and solid samples. Ammonia vapor released from ammonium salt after treatment with concentrated NaOH is transferred by argon to plasma for detection at 174.273 nm using axial argon plasma mode. The calibration curves were linear within a range of 25-1000 mg L(-1)N as ammonium molybdate with correlation coefficients of better than 0.99 and limits of detection of about 10-25mg L(-1)N. The percent recovery of N (25-500 mg L(-1)N) in soft (distilled) water and high salt content (1.7 mol L(-1) NaCl) matrices was found to be in the range of about 97-102% with %RSD in the range of 4.6-0.62. The sensitivity, limit of detection, and blank contribution from the atmospheric nitrogen, were tremendously improved in this method compared with the available ICP-AES spray chamber counterpart. Furthermore, the ICP-AES-HG method gave results for real samples (soil, fertilizer, waste water) containing about 50-1800 mg L(-1)N in good agreement with those obtained by the standard Kjeldahl method. No statistical differences at the 95% confidence level on applying the t-test were observed between the values obtained by the two methods. Thus, the ICP-AES-HG method is reliable and faster than the conventional tedious Kjeldahl method, superior to the ICP-AES spray chamber method, and almost free from matrix interference which is usually a critical factor in atomic emission spectroscopic techniques. PMID:19362191

  17. Calibration graphs for Ti, Ta and Nb in sintered tungsten carbide by infrared laser ablation inductively coupled plasma atomic emission spectrometry.

    PubMed

    Kanický, V; Otruba, V; Mermet, J M

    2001-12-01

    Infrared laser ablation (IR-LA) has been studied as a sample introduction technique for the analysis of sintered cobalt-cemented tungsten carbide materials by inductively coupled plasma atomic emission spectrometry (ICP-AES). Fractionation of cobalt was observed. Linearity of calibration plots was verified at least up to 15% Ti, 8% Ta, and 3% Nb. Above 1% (m/m) Ti, Ta, and Nb, the repeatability of results was better than 3% R.S.D. The relative uncertainty at the centroid of the calibration line was in the range from +/- 3% to +/- 4% for Ti, Ta, and Nb with internal standardization by tungsten and up to +/- 5% without internal standardization. The limits of detection were 0.004% Ti, 0.001% Ta, and 0.004% Nb. Elimination of the cemented hardmetal dissolution procedure is the main advantage of this method. PMID:11769803

  18. Evidence of weak plasma series resonance heating in the H-mode of neon and neon/argon inductively coupled plasmas

    NASA Astrophysics Data System (ADS)

    Boffard, John B.; Jung, R. O.; Lin, Chun C.; Aneskavich, L. E.; Wendt, A. E.

    2012-09-01

    Phase-resolved optical emission spectroscopy measurements in argon and neon inductively coupled plasmas (ICPs) have revealed a surplus of high-energy electrons in neon-containing plasmas. Differences between results of emission model analyses using neon and argon lines (as well as probe measurements) also indicate a high-energy enhancement in neon-containing plasmas. The abundance of these extra high-energy electrons is correlated with the sheath thickness near the rf antenna and can be reduced by either adding a Faraday shield (external shielding) or increasing the plasma density. A comparison of modelled and experimental values of the 13.56 MHz time modulation of select neon emission lines strongly suggests plasma series resonance heating adjacent to the ICP antenna as the source of the extra heating.

  19. Dry etch damage in GaAs metal-semiconductor field-effect transistors exposed to inductively coupled plasma and electron cyclotron resonance Ar plasmas

    SciTech Connect

    Ren, F.; Lee, J.W.; Abernathy, C.R.; Pearton, S.J.; Constantine, C.; Barratt, C.; Shul, R.J.

    1997-07-01

    The effects of Ar plasma exposure on transconductance, channel sheet resistance, output resistance, and gate contact ideality factor of GaAs metal-semiconductor field-effect transistors (MESFETs) were investigated using two different high-density plasma sources, namely inductively coupled plasma and electron resonance plasma. Ion-induced damage is found to be reduced at moderate source powers ({approximately}200W) because of the reduction in cathode dc self-bias and hence ion energy, but at higher source powers the increase in ion flux produces significant deterioration of the device performance. Careful attention must be paid to both ion flux and ion energy in order to minimize ion-induced damage. Due to their relatively low channel doping levels, MESFETs are found to be more sensitive to plasma damage than devices with very heavily doped component layers such as heterojunction bipolar transistors. {copyright} {ital 1997 American Vacuum Society.}

  20. Study of internal transport barrier triggering mechanism in tokamak plasmas

    SciTech Connect

    Dong, J.Q.; Mou, Z.Z.; Long, Y.X.; Mahajan, S.M.

    2004-12-01

    Sheared flow layers driven by magnetic energy, released in tearing-reconnection processes inherent in dissipative magnetohydrodynamics, are proposed as a triggering mechanism for the creation of the internal transport barrier (ITB) in tokamak plasmas. The double tearing mode, mediated by anomalous electron viscosity in configurations with a nonmonotonic safety factor, is investigated as an example. Particular emphasis is placed on the formation of sheared poloidal flow layers in the vicinity of the magnetic islands. A quasilinear simulation demonstrates that the sheared flows induced by the mode have desirable characteristics (lying just outside the magnetic islands), and sufficient levels required for ITB formation. A possible explanation is also proffered for the experimental observation that the transport barriers are preferentially formed in the proximity of low-order rational surfaces.

  1. Plasma Hazards and Acceptance for International Space Station Extravehicular Activities

    NASA Astrophysics Data System (ADS)

    Patton, Thomas

    2010-09-01

    Extravehicular activity(EVA) is accepted by NASA and other space faring agencies as a necessary risk in order to build and maintain a safe and efficient laboratory in space. EVAs are used for standard construction and as contingency operations to repair critical equipment for vehicle sustainability and safety of the entire crew in the habitable volume. There are many hazards that are assessed for even the most mundane EVA for astronauts, and the vast majority of these are adequately controlled per the rules of the International Space Station Program. The need for EVA repair and construction has driven acceptance of a possible catastrophic hazard to the EVA crewmember which cannot currently be controlled adequately. That hazard is electrical shock from the very environment in which they work. This paper describes the environment, causes and contributors to the shock of EVA crewmembers attributed to the ionospheric plasma environment in low Earth orbit. It will detail the hazard history, and acceptance process for the risk associated with these hazards that give assurance to a safe EVA. In addition to the hazard acceptance process this paper will explore other factors that go into the decision to accept a risk including criticality of task, hardware design and capability, and the probability of hazard occurrence. Also included will be the required interaction between organizations at NASA(EVA Office, Environments, Engineering, Mission Operations, Safety) in order to build and eventually gain adequate acceptance rationale for a hazard of this kind. During the course of the discussion, all current methods of mitigating the hazard will be identified. This paper will capture the history of the plasma hazard analysis and processes used by the International Space Station Program to formally assess and qualify the risk. The paper will discuss steps that have been taken to identify and perform required analysis of the floating potential shock hazard from the ISS environment

  2. Dusty Plasma Physics Facility for the International Space Station

    NASA Astrophysics Data System (ADS)

    Goree, John; Hahn, Inseob

    2015-09-01

    The Dusty Plasma Physics Facility (DPPF) is an instrument planned for the International Space Station (ISS). If approved by NASA, JPL will build and operate the facility, and NASA will issue calls for proposals allowing investigators outside JPL to carry out research, public education, and outreach. Microgravity conditions on the ISS will be useful for eliminating two unwanted effects of gravity: sedimentation of dust particles to the bottom of a plasma chamber, and masking weak forces such as the ion drag force that act on dust particles. The DPPF facility is expected to support multiple scientific users. It will have a modular design, with a scientific locker, or insert, that can be exchanged without removing the entire facility. The first insert will use a parallel-plate radio-frequency discharge, polymer microspheres, and high-speed video cameras. This first insert will be designed for fundamental physics experiments. Possible future inserts could be designed for other purposes, such as engineering applications, and experimental simulations of astrophysical or geophysical conditions. The design of the facility will allow remote operation from ground-based laboratories, using telescience.

  3. Determination of lead, cadmium and mercury in blood for assessment of environmental exposure: A comparison between inductively coupled plasma mass spectrometry and atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Palmer, Christopher D.; Lewis, Miles E.; Geraghty, Ciaran M.; Barbosa, Fernando; Parsons, Patrick J.

    2006-08-01

    A biomonitoring method for the determination of Pb, Cd, and Hg at background levels in whole blood by inductively coupled plasma-mass spectrometry is described. While this method was optimized for assessing Pb, Cd and Hg at environmental levels, it also proved suitable for assessing concentrations associated with occupational exposure. The method requires as little as 200 μl of blood that is diluted 1 + 49 for direct analysis in the inductively coupled plasma-mass spectrometer. Method performance is compared to well-established AAS methods. Initial method validation was accomplished using National Institute of Standards and Technology (NIST) Standard Reference Material 966, Toxic Metals in Bovine Blood. Method detection limits (3s) are 0.05 μg dl - 1 for Pb, 0.09 μg l - 1 for Cd; and 0.17 μg l - 1 for Hg. Repeatability ranged from 1.4% to 2.8% for Pb; 3% to 10% for Cd; and 2.6% to 8.8% for Hg. In contrast, AAS method detection limits were 1 μg dl - 1 , 0.54 μg l - 1 , and 0.6 μg l - 1 , for Pb, Cd, and Hg, respectively. Further performance assessments were conducted over a 2-year period via participation in four international External Quality Assessment Schemes (EQAS) operated specifically for toxic metals in blood. This includes schemes operated by (a) the New York State Department of Health's Wadsworth Center, Albany, NY, USA (b) L'Institut National de Santé Publique du Québec, Centre de Toxicologie du Québec, Canada, (c) Friedrich-Alexander University, Erlangen, Germany, and (d) the University of Surrey, Guildford, UK Trace Elements scheme. The EQAS data reflect analytical performance for blind samples analyzed independently by both inductively coupled plasma-mass spectrometry and AAS methods.

  4. Summary of the 2012 Inductive Pulsed Plasma Thruster Development and Testing Program

    NASA Technical Reports Server (NTRS)

    Polzin, K. A.; Martin, A. K.; Eskridge, R. H.; Kimberlin, A. C.; Addona, B. M.; Devineni, A. P.; Dugal-Whitehead, N. R.; Hallock, A. K.

    2013-01-01

    Inductive pulsed plasma thrusters are spacecraft propulsion devices in which energy is capacitively stored and then discharged through an inductive coil. While these devices have shown promise for operation at high efficiency on a range of propellants, many technical issues remain before they can be used in flight applications. A conical theta-pinch thruster geometry was fabricated and tested to investigate potential improvements in propellant utilization relative to more common, flat-plate planar coil designs. A capacitor charging system is used to permit repetitive discharging of thrusters at multiple cycles per second, with successful testing accomplished at a repetition-rate of 5 Hz at power levels of 0.9, 1.6, and 2.5 kW. The conical theta-pinch thruster geometry was tested at cone angles of 20deg, 38deg, and 60deg, with single-pulse operation at 500 J/pulse and repetitionrate operation with the 38deg model quantified through direct thrust measurement using a hanging pendulum thrust stand. A long-lifetime valve was designed and fabricated, and initial testing was performed to measure the valve response and quantify the leak rate at beginning-of-life. Subscale design and testing of a capacitor charging system required for operation on a spacecraft is reported, providing insights into the types of components needed in the circuit topology employed. On a spacecraft, this system would accept as input a lower voltage from the spacecraft DC bus and boost the output to the high voltage required to charge the capacitors of the thruster.

  5. PREFACE: 3rd International Workshop on Infrared Plasma Spectroscopy

    NASA Astrophysics Data System (ADS)

    Davies, P. B.; Röpcke, Jürgen; Hempel, Frank

    2009-07-01

    the scientific committee felt that this time it would be useful to emphasise new spectroscopic developments as well as covering applications. This might serve as a guide as to where the subject of infrared spectroscopy in combination with plasma sources might be heading in the future i.e. to emphasize pure infrared spectroscopy developments. The first invited lecture (G Guelachvili and N Picque) and the last invited lecture (F K Tittel, Y Bakhirkin, R Curl, A Kosterev, R Lewicki, D Thomasz and S So) were chosen to set the scene and realise this objective. The second (R Engeln, R Zijlmans, S Welzel, O Gabriel, J-P van Helden, J Röpcke and D Schram) and third (X Aubert, C Lazzaroni, D Marinov, O Guaitella, S Welzel, A Pipa, J Röpcke and A Rousseau) invited talks focussed on the application of the IR laser techniques with particular emphasis on the role of surfaces in plasmas and the relevance of plasma surface interactions. Surface plasma interactions did not feature strongly in the two earlier meetings and so this topic too, along with the emphasis on novel infrared spectroscopy techniques, represents a new direction for the conference. Paul B Davies and Jürgen Röpcke International Scientific Committee P B Davies, Cambridge, UK: Chair J Röpcke, Greifswald, Germany: Co-Chair R Engeln, Eindhoven, Netherlands G Hancock, Oxford, U K M Hori, Nagoya, Japan H Linnartz, Leiden, Netherlands R Martini, New York, USA J Meichsner, Greifswald, Germany A Rousseau, Paris, France Local Organizing Committee J Röpcke (INP: Chair) F Hempel (INP: Secretary) J Meichsner (IfP, University of Greifswald) N Lang (INP) L Glawe (INP) C Krcka (INP) B Lindemann (INP) Conference photograph

  6. Effects of magnetic field on pulse wave forms in plasma immersion ion implantation in a radio-frequency, inductively coupled plasma

    NASA Astrophysics Data System (ADS)

    Tong, Honghui; Fu, Ricky K. Y.; Tang, Deli; Zeng, Xuchu; Chu, Paul K.

    2002-09-01

    The time-dependent current wave forms measured using a pulse biased planar electrode in hydrogen radio-frequency (rf), inductively coupled plasma, plasma immersion ion implantation experiments are observed to vary in the presence of an external magnetic field B. Results further indicate that the magnitude of the pulse current is related to the strength and direction of the magnetic field, rf power, and pressure, but the pulse current curves can be primarily correlated with B. The plasma discharges are enhanced in all cases due to magnetic confinement of the electrons, enlargement of the plasma generation volume, and increase in the rf power absorbing efficiency. The plasma density diagnosed by Langmuir probe diminishes in front of the sample chuck with B, whereas the plasma is confined nearby the sidewall of the vacuum chamber at high magnetic field. The high degree of plasma density nonuniformity at high B in front of the sample chuck is not desirable for the processing of planar samples such as silicon wafers and must be compensated. The reduction in the plasma density and plasma density gradient in the sheath can be accounted for by the changes in the pulse current wave forms.

  7. Inductively coupled plasma -- Atomic emission spectroscopy glove box assembly system at the West Valley Demonstration Project

    SciTech Connect

    Marlow, J.H.; McCarthy, K.M.; Tamul, N.R.

    1999-12-17

    The inductively coupled plasma/atomic emission spectroscopy [ICP/AES (ICP)] system for elemental analyses in support of vitrification processing was first installed in 1986. The initial instrument was a Jobin Yvon (JY) Model JY-70 ICP that consisted of sequential and simultaneous spectrometers for analysis of nonradioactive samples as radioactive surrogates. The JY-70 ICP continued supporting nonradioactive testing during the Functional and Checkout Testing of Systems (FACTS) using the full-scale melter with ``cold'' (nonradioactive) testing campaigns. As a result, the need for another system was identified to allow for the analysis of radioactive samples. The Mass Spec (Spectrometry) Lab was established for the installation of the modified ICP system for handling radioactive samples. The conceptual setup of another ICP was predicated on the use of a hood to allow ease of accessibility of the torch, nebulizer, and spray chamber, and the minimization of air flow paths. However, reconsideration of the radioactive sample dose rate and contamination levels led to the configuration of the glovebox system with a common transfer interface box for the ICP and the inductively coupled plasma-mass spectrometer (ICP-MS) glovebox assemblies. As a result, a simultaneous Model JY-50P ICP with glovebox was installed in 1990 as a first generation ICP glovebox system. This was one of the first ICP glovebox assemblies connected with an ICP-MS glovebox system. Since the economics of processing high-level radioactive waste (HLW) required the availability of an instrument to operate 24 hours a day throughout the year without any downtime, a second generation ICP glovebox assembly was designed, manufactured, and installed in 1995 using a Model JY-46P ICP. These two ICP glovebox systems continue to support vitrification of the HLW into canisters for storage. The ICP systems have been instrumental in monitoring vitrification batch processing. To date, remote sample preparation and

  8. Control Capabilities of Low-Inductance-Antenna-Driven RF Plasmas for Low-Damage Processing of Polymers

    NASA Astrophysics Data System (ADS)

    Setsuhara, Yuichi; Takenaka, Kosuke; Cho, Ken; Ebe, Akinori; Shiratani, Masaharu; Sekine, Makoto; Hori, Masaru

    2008-10-01

    Low-damage processing of polymers is of key importance for fabrication of next-generation devices including electronics on polymers, which require development of plasma sources with reduced plasma potential in order to control interface between the polymer substrate and functional films without suffering degradations due to ion bombardment. Furthermore, applications to polymer-based displays and photovoltaic devices require ultra-large area processes at high throughput. To meet these requirements, we have developed plasma processing technologies with low-inductance antenna (LIA) modules to sustain inductively-coupled RF plasmas. Ion energy distributions showed considerably suppressed ion energy as low as 3.8 eV. The polymer surfaces after plasma exposure were analyzed via hard x-ray photoelectron spectroscopy (HXPES) at SPring8 (National SOR facility in Japan), which exhibited nano-surface modification of polymer surface without suffering degradation of molecular structures underneath. Furthermore, plasma-enhanced deposition of silicon films showed low-temperature (200 deg.C) formation of micro-crystalline silicon films due to sufficiently reduced damage during deposition.

  9. Inductively Coupled Plasma Etching of III-V Antimonides in BCl(3)/Ar and Cl(2)/Ar

    SciTech Connect

    Leavitt, R.P.; Lester, L.F.; Shul, R.J.; Willison, C.G.; Zhang, L.

    1998-11-04

    Inductively coupled plasma (ICP) etching characteristics of GaSb and AIGaAsSb have been investigated in BC13/Ar and Clz/Ar plasmas. The etch rates and selectivity between GaSb and AIGaAsSb are reported as functions of plasma chemistry, ICP power, RF self-bias, and chamber pressure. It is found that physical sputtering resorption of the etch products plays a dominant role in BC13/Ar ICP etching, while in Clz/Ar plasma, the chemical reaction dominates the etching. GaSb etch rates exceeding 2 ~rnhnin are achieved in Clz/Ar plasmas with smooth surfaces and anisotropic profiles. In BC13/Ar plasmas, etch rates of 5100 Mmin and 4200 Mmin are obtained for GaSb and AIGaAsSb, respectively. The surfaces of both GaSb and AIGaAsSb etched in BC13/Ar plasmas remain smooth and stoichiometric over the entire range of plasma conditions investigated. This result is attributed to effective removal of etch products by physical sputtering. For a wide range of plasma conditions, the selectivity between GaSb and AIGaAsSb is close to unity, which is desirable for fabricating etched mirrors and gratings for Sb-based mid-IR laser diodes.

  10. Resonant laser ablation of metals detected by atomic emission in a microwave plasma and by inductively coupled plasma mass spectrometry.

    PubMed

    Cleveland, Danielle; Stchur, Peter; Hou, Xiandeng; Yang, Karl X; Zhou, Jack; Michel, Robert G

    2005-12-01

    It has been shown that an increase in sensitivity and selectivity of detection of an analyte can be achieved by tuning the ablation laser wavelength to match that of a resonant gas-phase transition of that analyte. This has been termed resonant laser ablation (RLA). For a pulsed tunable nanosecond laser, the data presented here illustrate the resonant enhancement effect in pure copper and aluminum samples, chromium oxide thin films, and for trace molybdenum in stainless steel samples, and indicate two main characteristics of the RLA phenomenon. The first is that there is an increase in the number of atoms ablated from the surface. The second is that the bandwidth of the wavelength dependence of the ablation is on the order of 1 nm. The effect was found to be virtually identical whether the atoms were detected by use of a microwave-induced plasma with atomic emission detection, by an inductively coupled plasma with mass spectrometric detection, or by observation of the number of laser pulses required to penetrate through thin films. The data indicate that a distinct ablation laser wavelength dependence exists, probably initiated via resonant radiation trapping, and accompanied by collisional broadening. Desorption contributions through radiation trapping are substantiated by changes in crater morphology as a function of wavelength and by the relatively broad linewidth of the ablation laser wavelength scans, compared to gas-phase excitation spectra. Also, other experiments with thin films demonstrate the existence of a distinct laser-material interaction and suggest that a combination of desorption induced by electronic transition (DIET) with resonant radiation trapping could assist in the enhancement of desorption yields. These results were obtained by a detailed inspection of the effect of the wavelength of the ablation laser over a narrow range of energy densities that lie between the threshold of laser-induced desorption of species and the usual analytical

  11. Investigation of magnetic-pole-enhanced inductively coupled nitrogen-argon plasmas

    NASA Astrophysics Data System (ADS)

    Jan, F.; Khan, A. W.; Saeed, A.; Zakaullah, M.

    2012-09-01

    This article presented the features of the mixed mode and H mode in magnetic pole enhanced, inductively coupled Ar-N2 plasmas using RF-compensated Langmuir probe measurements. To fully characterize plasma parameters and electron energy probability functions (EEPFs), the gas pressure and argon content were varied. It was observed that with increasing the nitrogen content and gas pressure, the critical RF power to sustain H mode increases; this increase was more prominent for pure nitrogen discharge at higher pressure. The electron number density (ne) shows increasing trend with increasing RF power, while at higher gas pressures, the electron number density decreases at fixed RF power. Mostly, the EEPFs show a Maxwellian distribution even at low RF power (for higher argon content in the discharge) and at moderate RF power (for higher or pure nitrogen content in the discharge) for pressures of 15-60 mTorr. With increasing the nitrogen content in the mixture, the low energy part of the EEPF is more Druyvesteyn with a distorted high energy tail at low RF power. At fixed RF power, the slope of EEPF changes sharply with increasing pressure. It was observed that in hybrid mode, the EEPF at higher gas pressure (75 mTorr) in a pure nitrogen discharge shows a flat hole near the average electron energy of 3 eV and changes to Maxwellian distribution in H mode. The skin depth versus RF power shows that the skin depth is smaller than the critical dimension of the chamber, regardless of the gas type and the gas pressure.

  12. Electromagnetic wave attenuation measurements in a ring-shaped inductively coupled air plasma

    SciTech Connect

    Xiaolong, Wei; Haojun, Xu; Min, Lin; Chen, Su; Jianhai, Li

    2015-05-28

    An aerocraft with the surface, inlet and radome covered large-area inductive coupled plasma (ICP) can attenuate its radar echo effectively. The shape, thickness, and electron density (N{sub e}) distribution of ICP are critical to electromagnetic wave attenuation. In the paper, an air all-quartz ICP generator in size of 20 × 20 × 7 cm{sup 3} without magnetic confinement is designed. The discharge results show that the ICP is amorphous in E-mode and ring-shaped in H-mode. The structure of ICP stratifies into core region and edge halo in H-mode, and its width and thickness changes from power and pressure. Such phenomena are explained by the distribution of RF magnetic field, the diffusion of negative ions plasma and the variation of skin depth. In addition, the theoretical analysis shows that the N{sub e} achieves nearly uniform within the electronegative core and sharply steepens in the edge. The N{sub e} of core region is diagnosed by microwave interferometer under varied conditions (pressure in range of 10–50 Pa, power in 300–700 W). Furthermore, the electromagnetic wave attenuation measurements were carried out with the air ICP in the frequencies of 4–5 GHz. The results show that the interspaced ICP is still effective to wave attenuation, and the wave attenuation increases with the power and pressure. The measured attenuation is approximately in accordance with the calculation data of finite-different time-domain simulations.

  13. Induction of the Root Cell Plasma Membrane Ferric Reductase (An Exclusive Role for Fe and Cu).

    PubMed Central

    Cohen, C. K.; Norvell, W. A.; Kochian, L. V.

    1997-01-01

    Induction of ferric reductase activity in dicots and nongrass monocots is a well-recognized response to Fe deficiency. Recent evidence has shown that Cu deficiency also induces plasma membrane Fe reduction. In this study we investigated whether other nutrient deficiencies could also induce ferric reductase activity in roots of pea (Pisum sativum L. cv Sparkle) seedlings. Of the nutrient deficiencies tested (K, Mg, Ca, Mn, Zn, Fe, and Cu), only Cu and Fe deficiencies elicited a response. Cu deficiency induced an activity intermediate between Fe-deficient and control plant activities. To ascertain whether the same reductase is induced by Fe and Cu deficiency, concentration- and pH-dependent kinetics of root ferric reduction were compared in plants grown under control, -Fe, and -Cu conditions. Additionally, rhizosphere acidification, another process induced by Fe deficiency, was quantified in pea seedlings grown under the three regimes. Control, Fe-deficient, and Cu-deficient plants exhibited no major differences in pH optima or Km for the kinetics of ferric reduction. However, the Vmax for ferric reduction was dramatically influenced by plant nutrient status, increasing 16- to 38-fold under Fe deficiency and 1.5- to 4-fold under Cu deficiency, compared with that of control plants. These results are consistent with a model in which varying amounts of the same enzyme are deployed on the plasma membrane in response to plant Fe or Cu status. Rhizosphere acidification rates in the Cu-deficient plants were similarly intermediate between those of the control and Fe-deficient plants. These results suggest that Cu deficiency induces the same responses induced by Fe deficiency in peas. PMID:12223760

  14. The PERC{trademark} process: Existing and potential applications for induction coupled plasma technology in hazardous and radioactive waste treatment

    SciTech Connect

    Blutke, A.S.; Vavruska, J.S.; Serino, J.F.

    1996-12-31

    Plasma Technology, Inc. (PTI), a Santa Fe, New Mexico corporation has developed the Plasma Energy Recycle and Conversion (PERC){trademark} treatment process as a safe and environmentally clean alternative to conventional thermal destruction technologies. The PERC{trademark} treatment process uses as its heat source an advanced Induction Coupled Plasma (ICP) torch connected to a reaction chamber system with an additional emission control system. For example, organic-based gas, liquid, slurry, and/or solid waste streams can be converted into usable or even salable products while residual emissions are reduced to an absolute minimum. In applications for treatment of hazardous and radioactive waste streams, the PERC system could be used for destruction of the hazardous organic constituents and/or significant waste volume reduction while capturing the radioactive fraction in a non-leachable form. Like Direct Current (DC) and Alternating Current (AC) arc plasma systems, ICP torches offer sufficient energy to decompose, melt and/or vitrify any waste stream. The decision for an arc plasma or an IC plasma system has to be made on a case by case evaluation and is highly dependent on the specific waste stream`s form and composition. Induction coupled plasma technology offers one simple, but significant difference compared to DC or AC arc plasma systems: the ICP torch is electrodeless. To date, enormous research effort has been spent to improve the lifetime of electrodes and the effectiveness of related cooling systems. Arc plasma systems are established in research laboratories worldwide and are approaching a broad use in commercial applications. ICP technology has been improved relatively recently, but nowadays offers complete new and beneficial approaches in the field of waste conversion and treatment.

  15. Inductively coupled plasma-mass spectrometry: An emerging method for analysis of long-lived radionuclides

    SciTech Connect

    Ross, R.R.; Noyce, J.R.; Lardy, M.M.

    1993-12-31

    Inductively coupled plasma-mass spectrometry (ICP-MS) is a relatively new technique that can analyze for most of the elements in the periodic table at parts per billion (ng/mL) to parts per trillion (pg/mL). Already in use several years for trace analysis of stable isotopes, ICP-MS is becoming a powerful, complementary method to the counting of decay radiations for the analysis of radionuclides. Most radionuclides with half-lives longer than approximately 1x10{sup 3} years can be quantitatively detected on ICP-MS instruments that have an electrothermal vaporization unit for the injection of sample aliquants. Radionuclides with half-lives greater than approximately 1x10{sup 4} years can be measured routinely with greater sensitivity and more quickly by ICP-MS than by radiation counting. Examples from the literature of applying ICP-MS to radionuclides are the bioassay of uranium in urine, measurement of {sup 237}Np in soil and silt, and analysis for {sup 99}Tc in sea water, seaweed, and marine sediment. This paper discusses the instrumentation, advantages and limitations, and present and potential applications of ICP-MS for radionuclide measurements.

  16. Macro-loading Effects in Inductively Coupled Plasma Etched Mercury Cadmium Telluride

    NASA Astrophysics Data System (ADS)

    Apte, Palash; Rybnicek, Kimon; Stoltz, Andrew

    2016-05-01

    This paper reports the effect of macro-loading on mercury cadmium telluride (Hg1-x Cd x Te) and Photoresist (PR) etched in an inductively coupled plasma (ICP). A significant macro-loading effect is observed, which affects the etch rates of both PR and Hg1-x Cd x Te. It is observed that the exposed silicon area has a significant effect on the PR etch rate, but not on the Hg1-x Cd x Te etch rate. It is also observed that the exposed Hg1-x Cd x Te area has a significant effect on the etch rate of the PR, but the exposed PR area does not seem to have an effect on the Hg1-x Cd x Te etch rate. Further, the exposed Hg1-x Cd x Te area is shown to affect the etch rate of the Hg1-x Cd x Te, but there does not seem to be a similar effect for the exposed PR area on the etch rate of the PR. Since the macro-loading affects the selectivity significantly, this effect can cause significant problems in the etching of deep trenches. A few techniques to reduce the effect of macro-loading on the etch rates of the PR and Hg1-x Cd x Te are listed, herein.

  17. Scandium analysis in silicon-containing minerals by inductively coupled plasma tandem mass spectrometry

    NASA Astrophysics Data System (ADS)

    Whitty-Léveillé, Laurence; Drouin, Elisabeth; Constantin, Marc; Bazin, Claude; Larivière, Dominic

    2016-04-01

    This article reports on the development of a new method for the accurate and precise determination of the amount of scandium, Sc, in silicon-containing minerals, based on the use of tandem quadrupole inductively coupled plasma mass spectrometry (ICP-MS/MS). The tandem quadrupole instrument enables new mass filtering configurations, which can reduce polyatomic interferences during the determination of Sc in mineral matrices. He and O2 were used and compared as collision and reaction gases for the removal of interferences at m/z 45 and 61. Using helium gas was ineffective to overcome all of the spectral interferences observed at m/z 45 and particularly for Si-based interferences. However, conversion of Sc+ ions into ScO+ ions (after bombardment with O2 in the octopole reaction system coupled with the use of the instrument in MS/MS mass-shift mode) provided interference-free conditions and sufficiently low limits of detection, down to 3 ng L- 1, to accurately detect Sc. The accuracy of the proposed methodology was assessed by analyzing five different reference materials (BX-N, OKA-2, NIM-L, SY-3 and GH).

  18. Laser-ablation sampling for inductively coupled plasma distance-of-flight mass spectrometry

    SciTech Connect

    Gundlach-Graham, Alexander W.; Dennis, Elise; Ray, Steven J.; Enke, Christie G.; Barinaga, Charles J.; Koppenaal, David W.; Hieftje, Gary M.

    2015-01-01

    An inductively coupled plasma distance-of-flight mass spectrometer (ICP-DOFMS) has been coupled with laser-ablation (LA) sample introduction for the elemental analysis of solids. ICP-DOFMS is well suited for the analysis of laser-generated aerosols because it offers both high-speed mass analysis and simultaneous multi-elemental detection. Here, we evaluate the analytical performance of the LA-ICP-DOFMS instrument, equipped with a microchannel plate-based imaging detector, for the measurement of steady-state LA signals, as well as transient signals produced from single LA events. Steady-state detection limits are 1 mg g1, and absolute single-pulse LA detection limits are 200 fg for uranium; the system is shown capable of performing time-resolved single-pulse LA analysis. By leveraging the benefits of simultaneous multi-elemental detection, we also attain a good shot-to-shot reproducibility of 6% relative standard deviation (RSD) and isotope-ratio precision of 0.3% RSD with a 10 s integration time.

  19. Effect of silane/hydrogen ratio on microcrystalline silicon thin films by remote inductively coupled plasma

    NASA Astrophysics Data System (ADS)

    Guo, Y. N.; Wei, D. Y.; Xiao, S. Q.; Huang, S. Y.; Zhou, H. P.; Xu, S.

    2013-05-01

    Hydrogenated microcrystalline silicon (μc-Si:H) thin films were prepared by remote low frequency inductively coupled plasma (ICP) chemical vapor deposition system, and the effect of silane/hydrogen ratio on the microstructure and electrical properties of μc-Si:H films was systematically investigated. As silane/hydrogen ratio increases, the crystalline volume fraction Fc decreases and the ratio of the intensity of (220) peak to that of (111) peak drops as silane flow rate is increased. The FTIR result indicates that the μc-Si:H films prepared by remote ICP have a high optical response with a low hydrogen content, which is in favor of reducing light-induced degradation effect. Furthermore, the processing window of the phase transition region for remote ICP is much wider than that for typical ICP. The photosensitivity of μc-Si:H films can exceed 100 at the transition region and this ensures the possibility of the fabrication of microcrystalline silicon thin film solar cells with a open-circuit voltage of about 700 mV.

  20. Low temperature SiNx:H films deposited by inductively coupled plasma for solar cell applications

    NASA Astrophysics Data System (ADS)

    Zhou, H. P.; Wei, D. Y.; Xu, L. X.; Guo, Y. N.; Xiao, S. Q.; Huang, S. Y.; Xu, S.

    2013-01-01

    Amorphous hydrogenated silicon nitride thin films with different chemical compositions (SiNx:H) have been synthesized by using low frequency inductively coupled plasma of Si + N2 + H2 at a low temperature of 100 °C. The bonding configurations, bond density, hydrogen content, and chemical composition, as well as the refractive index are intensively investigated by a variety of characterization tools. Silicon nitride based antireflection layer on alkaline-textured silicon surface reduces the reflectivity to about 4%. As-deposited silicon nitride films exhibit an excellent passivation effect on p- and n-type Si. The surface recombination velocity is reduced to 36 cm/s on n-type silicon with resistivity of 2-3 Ω cm. The passivation effect originates from the H-related chemical passivation and fixed charge related field passivation. The growth mechanism of SiNx:H from the precursor gas of H2 diluted mixture of silane and nitrogen is also discussed.

  1. Highly sensitive immunoassay based on immunogold-silver amplification and inductively coupled plasma mass spectrometric detection.

    PubMed

    Liu, Rui; Liu, Xing; Tang, Yurong; Wu, Li; Hou, Xiandeng; Lv, Yi

    2011-03-15

    In this work, we demonstrated a highly sensitive inductively coupled plasma mass spectrometric (ICPMS) method for the determination of human carcinoembryonic antigen (CEA), which combined the inherent high sensitivity of elemental mass spectrometric measurement with the signal amplification of catalytic silver deposition on immunogold tags. The silver amplification procedure was easy to handle and required cheap reagents, and the sensitivity was greatly enhanced to 60-fold after a 15 min silver amplification procedure. The experimental conditions, including detection of gold and silver by ICPMS, immunoassay parameters, silver amplification parameters, analytical performance, and clinical serum samples analysis, were investigated. The ICPMS Ag signal intensity depends linearly on the logarithm of the concentration of human CEA over the range of 0.07-1000 ng mL(-1) with a limit of detection (LOD, 3σ) of 0.03 ng mL(-1) (i.e., 0.15 pM). The LOD of the proposed method is around 2 orders of magnitude lower than that by the widely used enzyme-linked immunosorbent assay (ELISA) and 1 order of magnitude lower than that by clinical routine chemiluminescence immunoassay (CLIA) or time-resolved fluoroimmunoassay (TRFIA) and conventional ICPMS immunoassay. The present strategy was applied to the determination of human CEA in clinical human serum samples, and the results were in good agreement with those obtained by chemiluminescence immunoassay. PMID:21348438

  2. Controlled synthesis of nickel ferrite nanocrystals with tunable properties using a novel induction thermal plasma method

    SciTech Connect

    Bastien, Samuel; Braidy, Nadi

    2013-12-07

    Nickel ferrite spinel nanopowders were synthesised using a solution spray radio-frequency inductively coupled plasma reactor over a wide range of compositions (Ni{sub x}Fe{sub 3-x}O{sub 4}, x ≤ 1), with metastable powders produced for x = 0, 0.25, and 0.5. X-ray fluorescence and X-ray diffraction coupled to Rietveld refinement show that this synthesis technique offers an excellent level of control over both the chemical and crystallographic composition of the nanopowder through the control of the input Fe/Ni ratio. The technique produces highly crystalline nanopowders without the need for post-synthesis annealing. A bulk Fe/Ni ratio ≥2 yields a pure spinel Ni{sub x}Fe{sub 3-x}O{sub 4} phase, whereas Fe/Ni ratio <2 results in the excess Ni partitioning to a secondary bunsenite (Ni{sub x},Fe{sub 1-x})O phase. Morphological analysis using transmission electron microscopy shows that two types of particles are produced in different parts of the reactor: a highly faceted powder with the truncated octahedron morphology and a smaller-sized random agglomerate. The faceted particles have a log-normal particle size distribution, with an average size of about 30 nm while the agglomerates have a characteristic length of ∼3–5 nm.

  3. Investigation of palladium and platinum levels in food by sector field inductively coupled plasma mass spectrometry.

    PubMed

    Frazzoli, Chiara; Cammarone, Roberta; Caroli, Sergio

    2007-05-01

    Over the last two decades, there has been increased concern regarding the impact of some noble metals, such as Pd and Pt, on human health. These elements pollute the environment due to their widespread use as catalytic converters and in medical applications. The risk they pose to human health and the environment is still controversial; however, literature data point to diet as an important source of uptake by the human body. Within this context, the total Pd and Pt content of several Italian food commodities has been investigated. A total of 90 samples, including flour products, vegetables and foodstuffs of animal origin (meat, milk and eggs), were collected and freeze-dried. Samples were analyzed by sector field inductively coupled plasma mass spectrometry (SF-ICP-MS) after chopping or crushing followed by freeze-drying and microwave (MW)-assisted acid digestion in a Class-100 clean-room. A mathematical approach was adopted to correct the mass signals for still unresolved interference (mDeltam = 300, 10 000). The lowest and highest concentrations of Pt, i.e. 17 and 93 ng kg(-1) (dry weight, dw), were found in vegetables and flour products, respectively. The lowest Pd level (2830 ng kg(-1) dw) was found in eggs and the highest (47 800 ng kg(-1) dw) in vegetables. PMID:17487666

  4. Plutonium determination in seawater by inductively coupled plasma mass spectrometry: A review.

    PubMed

    Cao, Liguo; Bu, Wenting; Zheng, Jian; Pan, Shaoming; Wang, Zhongtang; Uchida, Shigeo

    2016-05-01

    Knowing the concentration and isotopic ratio of Pu in seawater is of critical importance for assessing Pu contamination and investigating oceanic processes. In recent decades, the concentration of (239+240)Pu in seawater, particularly for surface seawater, has presented an exponential decreasing trend with time; thus determination of Pu in seawater has become a challenge nowadays. Here, we have summarized and critically discussed a variety of reported analytical methods for Pu determination in seawater sample based on inductively coupled plasma mass spectrometry (ICP-MS) analytical technique for rapid ultra-trace detection of Pu. Generally, pretreatments for seawater sample include co-precipitation, valence adjustment and chemical separation and purification procedures, all of which are comprehensively reviewed. Overall, the selected anion-exchange, extraction resins and operation condition are important for decontamination of interference from matrix elements and achieving satisfactory chemical yields. In addition, other mass spectrometric and radiometric detections are briefly addressed and compared with the focus on assessing ICP-MS. Finally, we discuss some issues and prospects in determination and application of Pu isotopes in seawater samples for future research. PMID:26946007

  5. Macro-loading Effects in Inductively Coupled Plasma Etched Mercury Cadmium Telluride

    NASA Astrophysics Data System (ADS)

    Apte, Palash; Rybnicek, Kimon; Stoltz, Andrew

    2016-09-01

    This paper reports the effect of macro-loading on mercury cadmium telluride (Hg1- x Cd x Te) and Photoresist (PR) etched in an inductively coupled plasma (ICP). A significant macro-loading effect is observed, which affects the etch rates of both PR and Hg1- x Cd x Te. It is observed that the exposed silicon area has a significant effect on the PR etch rate, but not on the Hg1- x Cd x Te etch rate. It is also observed that the exposed Hg1- x Cd x Te area has a significant effect on the etch rate of the PR, but the exposed PR area does not seem to have an effect on the Hg1- x Cd x Te etch rate. Further, the exposed Hg1- x Cd x Te area is shown to affect the etch rate of the Hg1- x Cd x Te, but there does not seem to be a similar effect for the exposed PR area on the etch rate of the PR. Since the macro-loading affects the selectivity significantly, this effect can cause significant problems in the etching of deep trenches. A few techniques to reduce the effect of macro-loading on the etch rates of the PR and Hg1- x Cd x Te are listed, herein.

  6. Inductively coupled plasma mass spectrometer with laser ablation metal ions release detection in the human mouth

    NASA Astrophysics Data System (ADS)

    Kueerova, Hana; Dostalova, Tatjana; Prochazkova, J.

    2002-06-01

    Presence of more dental alloys in oral cavity often causes pathological symptoms. Due to various and multi-faced symptomatology, they tend to be a source of significant problems not only for the patient but also for the dentist. Metal ions released from alloys can cause subjective and objective symptoms in mouth. The aim of this study was detection of metal elements presence in saliva. There were 4 groups of examined persons: with intact teeth (15 individuals) with metallic restorations, pathological currents 5-30 (mu) A, multi-faced subjective symptomatology and uncharacteristic objective diagnosis (32 patients), with metallic restorations and no subjective symptoms (14 persons) and with metallic restorations, without pathological currents and with problems related to galvanism (13 patients). Presence of 14 metal elements was checked by inductively coupled plasma mass spectrometer with laser ablation. Nd:YAG laser detector was used. There were significant differences in content of silver, gold and mercury between persons with intact teeth and other three groups. There were no differences found between subjects with and without galvanic currents, and presence of subjective and objective symptoms.

  7. Elemental Bioimaging by Means of Fast Scanning Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Wehe, Christoph A.; Thyssen, Georgina M.; Herdering, Christina; Raj, Indra; Ciarimboli, Giuliano; Sperling, Michael; Karst, Uwe

    2015-08-01

    One of the most common setups for elemental bioimaging, the hyphenation of a laser ablation (LA) system and an inductively coupled plasma mass spectrometer (ICP-MS), was expanded by adding full scan mass spectrometric information as another dimension of information. While most studies deal with the analysis of typically not more than up to 10 isotopes per scan cycle, a fast scanning quadrupole mass analyzer was utilized to record the full mass spectrum of interest in this work. Mass-to-charge ratios from 6 to 250 were observed within one cycle. Besides the x- and y-position on the ablated sample and the intensity, the m/z-ratio served as fourth variable for each pixel of the obtained data, closing thereby the gap between "inorganic" and "organic" mass spectrometric imaging techniques. The benefits of this approach include an improved control of interferences, the discovery of unexpected elemental distributions, the possibility to plot isotopic ratios, and to integrate the intensities of a certain number of mass channels recorded for each isotope, thus virtually increasing sensitivity. The respective data are presented for dried droplets as well as embedded animal and human tissue slices. Limits of detection were calculated and found to be in accordance with counting statistics. A dedicated software macro was developed for data manipulation prior to common evaluation and image creation.

  8. Determination of metals in marine species by microwave digestion and inductively coupled plasma mass spectrometry analysis

    NASA Astrophysics Data System (ADS)

    Yang, Karl X.; Swami, Kamal

    2007-10-01

    A microwave digestion method suitable for determination of multiple elements in marine species was developed, with the use of cold vapor atomic spectrometry for the detection of Hg, and inductively coupled plasma mass spectrometry for all of the other elements. An optimized reagent mixture composed of 2 ml of HNO 3, 2 ml of H 2O 2 and 0.3 ml of HF used in microwave digestion of about 0.15 g (dry weight) of sample was found to give the best overall recoveries of metals in two standard reference materials. In the oyster tissue standard reference material (SRM 1566b), recoveries of Na, Al, K, V, Co, Zn, Se, Sr, Ag, Cd, Ni, and Pb were between 90% and 110%; Mg, Mn, Fe, Cu, As, and Ba recoveries were between 85% and 90%; Hg recovery was 81%; and Ca recovery was 64%. In a dogfish certified reference material (DORM-2), the recoveries of Al, Cr, Mn, Se, and Hg were between 90% and 110%; Ni, Cu, Zn, and As recoveries were about 85%; and Fe recovery was 112%. Method detection limits of the elements were established. Metal concentrations in flounder, scup, and blue crab samples collected from coastal locations around Long Island and in the Hudson River estuary were determined.

  9. Direct determination of metals in organics by inductively coupled plasma atomic emission spectrometry in aqueous matrices.

    PubMed

    Wang, Tiebang; Jia, Xiujuan; Wu, Jane

    2003-11-24

    A simple method for the simultaneous determination of up to 21 elements in organic matrices is proposed. Organic samples are simply dispersed in concentrated nitric acid by sonication, and the resulting emulsions/suspensions are directly aspirated into an inductively coupled plasma atomic emission spectrometer (ICP-AES) calibrated with aqueous standards for analysis. Proof of concept was provided by the excellent recoveries for the analysis of a 21-element metallo-organic standard. In addition, the results obtained using this method for a waste oil sample compared favorably with those from a method that utilized microwave digestion for sample preparation. Comparable results were also obtained by dilution in an organic solvent followed by ICP-AES analysis with an ultrasonic nebulizer equipped with a membrane desolvator. Furthermore, the viability and validity of this method were confirmed by the analysis of the National Institute of Standards and Technology standard reference material 1084a Wear-Metals in Lubricating Oil. Spike recoveries ranged from 83 to 105% and the limits of quantitation were 6 microg g(-1) or less for all the elements analyzed. PMID:14623589

  10. Oxygen bomb combustion of biological samples for inductively coupled plasma optical emission spectrometry

    NASA Astrophysics Data System (ADS)

    Souza, Gilberto B.; Carrilho, Elma Neide V. M.; Oliveira, Camila V.; Nogueira, Ana Rita A.; Nóbrega, Joaquim A.

    2002-12-01

    A rapid sample preparation method is proposed for decomposition of milk powder, corn bran, bovine and fish tissues, containing certified contents of the analytes. The procedure involves sample combustion in a commercial stainless steel oxygen bomb operating at 25 bar. Most of the samples were decomposed within 5 min. Diluted nitric acid or water-soluble tertiary amines 10% v/v were used as absorption solutions. Calcium, Cu, K, Mg, Na, P, S and Zn were recovered with the bomb washings and determined by inductively coupled plasma optical emission spectrometry (ICP-OES). Ethanol mixed with paraffin was used as a combustion aid to allow complete combustion. A cooling step prior releasing of the bomb valve was employed to increase the efficiency of sample combustion. Iodine was also determined in milk samples spiked with potassium iodide to evaluate the volatilization and collection of iodine in amine CFA-C medium and the feasibility of its determination by ICP-OES with axial view configuration. Most of the element recoveries in the samples were between 91 and 105% and the certified and found contents exhibited a fair agreement at a 95% confidence level.

  11. Determination of cobalamins using capillary electrophoresis inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Baker, S. A.; Miller-Ihli, N. J.

    2000-12-01

    The determination of cobalamins using capillary electrophoresis inductively coupled plasma mass spectrometry (CE-ICP-MS) was investigated. Both capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC) modes of operation were studied. The optimal separation of four cobalamin species (cyanocobalamin, hydroxocobalamin, methylcobalamin, and 5'-deoxyadenosylcobalamin) and a potentially harmful corrinoid analogue (cobinamide dicyanide) was obtained using CZE at a pH of 2.5. Both 20 mM phosphate and 20 mM formate buffers were used with success, although the formate buffer provided improved resolution. The CZE-ICP-MS method was used to quantify cyanocobalamin in a vitamin supplement and the analytical results were in good agreement (±5%) with values obtained by ICP-MS for total Co levels. The solution detection limits for cobalamins using CZE-ICP-MS were approximately 50 ng/ml. MEKC was found to be useful for the screening of vitamin preparations because it provided a rapid means of distinguishing cyanocobalamin (the form most commonly used in vitamin preparations) from free cobalt. The separation of free cobalt and cyanocobalamin using MEKC was achieved in less than 10 min.

  12. Determination of long-lived actinides in soil leachates by inductively coupled plasma: Mass spectrometry

    SciTech Connect

    Crain, J.S.; Smith, L.L.; Yaeger, J.S.; Alvarado, J.A.

    1994-06-01

    Inductively coupled plasma -- mass spectrometry (ICP-MS) was used to concurrently determine multiple long-lived (t{sub 1/2} > 10{sup 4} y) actinide isotopes in soil samples. Ultrasonic nebulization was found to maximize instrument sensitivity. Instrument detection limits for actinides in solution ranged from 50 mBq L{sup {minus}1} ({sup 239}Pu) to 2 {mu}Bq L{sup {minus}1} ({sup 235}U) Hydride adducts of {sup 232}Th and {sup 238}U interfered with the determinations of {sup 233}U and {sup 239} Pu; thus, extraction chromatography was, used to eliminate the sample matrix, concentrate the analytes, and separate uranium from the other actinides. Alpha spectrometric determinations of {sup 230}Th, {sup 239}Pu, and the {sup 234}U/{sup 238}U activity ratio in soil leachates compared well with ICP-MS determinations; however, there were some small systematic differences (ca. 10%) between ICP-MS and a-spectrometric determinations of {sup 234}U and {sup 238}U activities.

  13. Spark ablation-inductively coupled plasma spectrometry for analysis of geologic materials

    USGS Publications Warehouse

    Golightly, D.W.; Montaser, A.; Smith, B.L.; Dorrzapf, A.F., Jr.

    1989-01-01

    Spark ablation-inductively coupled plasma (SA-ICP) spectrometry is applied to the measurement of hafnium-zirconium ratios in zircons and to the determination of cerium, cobalt, iron, lead, nickel and phosphorus in ferromanganese nodules. Six operating parameters used for the high-voltage spark and argon-ICP combination are established by sequential simplex optimization of both signal-to-background ratio and signal-to-noise ratio. The time-dependences of the atomic emission signals of analytes and matrix elements ablated from a finely pulverized sample embedded in a pressed disk of copper demonstrate selective sampling by the spark. Concentration ratios of hafnium to zirconium in zircons are measured with a precision of 4% (relative standard deviation, RSD). For ferromanganese nodules, spectral measurements based on intensity ratios of analyte line to the Mn(II) 257.610 nm line provide precisions of analysis in the range from 7 to 14% RSD. The accuracy of analysis depends on use of standard additions of the reference material USGS Nod P-1, and an independent measurement of the Mn concentration. ?? 1989.

  14. Rapid determination of uranium isotopes in urine by inductively coupled plasma-mass spectrometry.

    PubMed

    Shi, Y; Dai, X; Collins, R; Kramer-Tremblay, S

    2011-08-01

    Following a radiological or nuclear emergency involving uranium exposure, rapid analytical methods are needed to analyze the concentration of uranium isotopes in human urine samples for early dose assessment. The inductively coupled plasma mass spectrometry (ICP-MS) technique, with its high sample throughput and high sensitivity, has advantages over alpha spectrometry for uranium urinalysis after minimum sample preparation. In this work, a rapid sample preparation method using an anion exchange chromatographic column was developed to separate uranium from the urine matrix. A high-resolution sector field ICP-MS instrument, coupled with a high sensitivity desolvation sample introduction inlet, was used to determine uranium isotopes in the samples. The method can analyze up to 24 urine samples in two hours with the limits of detection of 0.0014, 0.10, and 2.0 pg mL(-1) for (234)U, (235)U, and (238)U, respectively, which meet the requirement for isotopic analysis of uranium in a radiation emergency. PMID:21709502

  15. In situ determination of the static inductance and resistance of a plasma focus capacitor bank

    SciTech Connect

    Saw, S. H.; Lee, S.; Roy, F.; Chong, P. L.; Vengadeswaran, V.; Sidik, A. S. M.; Leong, Y. W.; Singh, A.

    2010-05-15

    The static (unloaded) electrical parameters of a capacitor bank are of utmost importance for the purpose of modeling the system as a whole when the capacitor bank is discharged into its dynamic electromagnetic load. Using a physical short circuit across the electromagnetic load is usually technically difficult and is unnecessary. The discharge can be operated at the highest pressure permissible in order to minimize current sheet motion, thus simulating zero dynamic load, to enable bank parameters, static inductance L{sub 0}, and resistance r{sub 0} to be obtained using lightly damped sinusoid equations given the bank capacitance C{sub 0}. However, for a plasma focus, even at the highest permissible pressure it is found that there is significant residual motion, so that the assumption of a zero dynamic load introduces unacceptable errors into the determination of the circuit parameters. To overcome this problem, the Lee model code is used to fit the computed current trace to the measured current waveform. Hence the dynamics is incorporated into the solution and the capacitor bank parameters are computed using the Lee model code, and more accurate static bank parameters are obtained.

  16. Fundamental and methodological investigations for the improvement of elemental analysis by inductively coupled plasma mass soectrometry

    SciTech Connect

    Ebert, Christopher Hysjulien

    2012-01-01

    This dissertation describes a variety of studies meant to improve the analytical performance of inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation (LA) ICP-MS. The emission behavior of individual droplets and LA generated particles in an ICP is studied using a high-speed, high frame rate digital camera. Phenomena are observed during the ablation of silicate glass that would cause elemental fractionation during analysis by ICP-MS. Preliminary work for ICP torch developments specifically tailored for the improvement of LA sample introduction are presented. An abnormal scarcity of metal-argon polyatomic ions (MAr{sup +}) is observed during ICP-MS analysis. Evidence shows that MAr{sup +} ions are dissociated by collisions with background gas in a shockwave near the tip of the skimmer cone. Method development towards the improvement of LA-ICP-MS for environmental monitoring is described. A method is developed to trap small particles in a collodion matrix and analyze each particle individually by LA-ICP-MS.

  17. Optimization of inductively coupled plasma deep etching of GaN and etching damage analysis

    NASA Astrophysics Data System (ADS)

    Qiu, Rongfu; Lu, Hai; Chen, Dunjun; Zhang, Rong; Zheng, Youdou

    2011-01-01

    Inductively coupled plasma (ICP) etching of GaN with an etching depth up to 4 μm is systemically studied by varying ICP power, RF power and chamber pressure, respectively, which results in etch rates ranging from ∼370 nm/min to 900 nm/min. The surface morphology and damages of the etched surface are characterized by optical microscope, scanning electron microscope, atomic force microscopy, cathodoluminescence mapping and photoluminescence (PL) spectroscopy. Sub-micrometer-scale hexagonal pits and pillars originating from part of the structural defects within the original GaN layer are observed on the etched surface. The density of these surface features varies with etching conditions. Considerable reduction of PL band-edge emission from the etched GaN surface indicates that high-density non-radiative recombination centers are created by ICP etching. The density of these non-radiative recombination centers is found largely dependent on the degree of physical bombardments, which is a strong function of the RF power applied. Finally, a low-surface-damage etch recipe with high ICP power, low RF power, high chamber pressure is suggested.

  18. Determination of mercury in whole blood and urine by inductively coupled plasma mass spectrometry.

    PubMed

    Fong, Bonnie Mei Wah; Siu, Tak Shing; Lee, Joseph Sai Kit; Tam, Sidney

    2007-06-01

    The conventional method for the determination of mercury in clinical samples is cold vapor atomic absorption spectrometry. Sample digestion or pretreatment require large sample volume and long sample preparation time. The inductively coupled plasma mass spectrometry (ICP-MS) method developed in this study requires only 100 microL of sample with practically no preparation, except for dilution with diluent. Significant savings in sample volumes, reagents, technician time, and analysis time are realized. Among different types of diluents, the one containing acid, tert-butanol, and potassium dichromate gave the best results to remove the mercury memory effect. The interassay precisions for whole blood and urine were < 5% and < 8%, respectively, and the intra-assay precisions were < 3% and < 7%, respectively. The lower limits of detection were 0.13, 0.17, and 0.26 microg/L for aqueous standard, urine, and whole blood, respectively. The developed ICP-MS method correlated well with the atomic absorption method and can offer an alternative to the atomic absorption method for mercury analysis with less sample volume requirement as well as shorter analysis time. PMID:17579973

  19. Determination of metals in Brazilian soils by inductively coupled plasma mass spectrometry.

    PubMed

    de Carvalho, Rui M; dos Santos, Jéssica A; Silva, Jessee A S; do Prado, Thiago G; da Fonseca, Adriel Ferreira; Chaves, Eduardo S; Frescura, Vera L A

    2015-08-01

    The concentration of metals in Brazilian soil under no-tillage (NT) and an area under native vegetation (NV) was determined by inductively coupled plasma mass spectrometry. The applied method was based on microwave-assisted acid digestion using HNO3, HCl, H2O2, and HF. The accuracy of the method was evaluated by analyzing two certified reference materials (BCR-142 and RS-3). The relative standard deviation for all target elements was below 8% indicating an adequate precision and the limit of detection ranged from 0.03 μg g(-1) (Cd) to 24.0 μg g(-1) (Fe). The concentrations of Al, As, Ba, Cd, Cu, Fe, Mg, Mn, Ni, Pb, Sr, and Zn in the different layers (0-10, 10-20, 20-40, and 40-60 cm) were determined in two types of soils, located in Paraná State in Brazil. The soil layers analysis revealed a different behavior of metals concentrations in soil samples under NT and NV. The obtained results showed a clear impact of anthropogenic action with respect to specific metals due to many years of uncontrolled application rates of limestone and phosphate fertilizers. PMID:26220781

  20. Using inductively coupled plasma-mass spectrometry for calibration transfer between environmental CRMs.

    PubMed

    Turk, G C; Yu, L L; Salit, M L; Guthrie, W F

    2001-06-01

    Multielement analyses of environmental reference materials have been performed using existing certified reference materials (CRMs) as calibration standards for inductively coupled plasma-mass spectrometry. The analyses have been performed using a high-performance methodology that results in comparison measurement uncertainties that are significantly less than the uncertainties of the certified values of the calibration CRM. Consequently, the determined values have uncertainties that are very nearly equivalent to the uncertainties of the calibration CRM. Several uses of this calibration transfer are proposed, including, re-certification measurements of replacement CRMs, establishing traceability of one CRM to another, and demonstrating the equivalence of two CRMs. RM 8704, a river sediment, was analyzed using SRM 2704, Buffalo River Sediment, as the calibration standard. SRM 1632c, Trace Elements in Bituminous Coal, which is a replacement for SRM 1632b, was analyzed using SRM 1632b as the standard. SRM 1635, Trace Elements in Subbituminous Coal, was also analyzed using SRM 1632b as the standard. PMID:11451248

  1. Separation Of Uranium And Plutonium Isotopes For Measurement By Multi Collector Inductively Coupled Plasma Mass Spectroscopy

    SciTech Connect

    Martinelli, R E; Hamilton, T F; Williams, R W; Kehl, S R

    2009-03-29

    Uranium (U) and plutonium (Pu) isotopes in coral soils, contaminated by nuclear weapons testing in the northern Marshall Islands, were isolated by ion-exchange chromatography and analyzed by mass spectrometry. The soil samples were spiked with {sup 233}U and {sup 242}Pu tracers, dissolved in minerals acids, and U and Pu isotopes isolated and purified on commercially available ion-exchange columns. The ion-exchange technique employed a TEVA{reg_sign} column coupled to a UTEVA{reg_sign} column. U and Pu isotope fractions were then further isolated using separate elution schemes, and the purified fractions containing U and Pu isotopes analyzed sequentially using multi-collector inductively coupled plasma mass spectrometer (MCICP-MS). High precision measurements of {sup 234}U/{sup 235}U, {sup 238}U/{sup 235}U, {sup 236}U/{sup 235}U, and {sup 240}Pu/{sup 239}Pu in soil samples were attained using the described methodology and instrumentation, and provide a basis for conducting more detailed assessments of the behavior and transfer of uranium and plutonium in the environment.

  2. Inductively coupled plasma mass spectrometry determination of metals in honeybee venom.

    PubMed

    Kokot, Zenon J; Matysiak, Jan

    2008-11-01

    Inductively coupled plasma mass spectrometry (ICP-MS) technique was used to analyze the contamination of selected 20 metals in 32 samples of honeybee venom and to demonstrate differences in the content of these elements. Among the analyzed metal microelements (Al, Co, Cu, Zn, Mn, Mo, B, V, Sr and Ni), macro-elements (Ca, Mg, K and Na) and toxic metals (As, Ba, Pb, Cd, Sb and Cr) were identified. The presented results showed that the metal levels in honeybee venom are much lower than the tolerable upper intake levels for the elements. Also the toxic metal contamination is much lower than the permissible levels for drugs established by the United States Pharmacopeia and the European Pharmacopeia. As opposed to the pharmacopeial tests for metals, a multi-element ICP-MS method has been developed. In order to confirm data obtained, the following steps and parameters were taken into account for the validation of the method: calibration verification, recovery, accuracy, precision, detection limit (LOD), quantitation limit (LOQ), spectral and matrix interference and comparison between ICP-MS and GFAAS (graphite furnace atomic absorption spectrometry) for Mn. All steps of validation proved the accuracy of the results. This is most likely the first study in which the metal content in honeybee venom was evaluated by ICP-MS. PMID:18617350

  3. Inductively coupled plasma atomic fluorescence spectrometric determination of cadmium, copper, iron, lead, manganese and zinc

    USGS Publications Warehouse

    Sanzolone, R.F.

    1986-01-01

    An inductively coupled plasma atomic fluorescence spectrometric method is described for the determination of six elements in a variety of geological materials. Sixteen reference materials are analysed by this technique to demonstrate its use in geochemical exploration. Samples are decomposed with nitric, hydrofluoric and hydrochloric acids, and the residue dissolved in hydrochloric acid and diluted to volume. The elements are determined in two groups based on compatibility of instrument operating conditions and consideration of crustal abundance levels. Cadmium, Cu, Pb and Zn are determined as a group in the 50-ml sample solution under one set of instrument conditions with the use of scatter correction. Limitations of the scatter correction technique used with the fluorescence instrument are discussed. Iron and Mn are determined together using another set of instrumental conditions on a 1-50 dilution of the sample solution without the use of scatter correction. The ranges of concentration (??g g-1) of these elements in the sample that can be determined are: Cd, 0.3-500; Cu, 0.4-500; Fe, 85-250 000; Mn, 45-100 000; Pb, 5-10 000; and Zn, 0.4-300. The precision of the method is usually less than 5% relative standard deviation (RSD) over a wide concentration range and acceptable accuracy is shown by the agreement between values obtained and those recommended for the reference materials.

  4. Imaging mass spectrometry in biological tissues by laser ablation inductively coupled plasma mass spectrometry.

    PubMed

    Becker, J S; Becker, J Su; Zoriy, M V; Dobrowolska, J; Matucsh, A

    2007-01-01

    Of all the inorganic mass spectrometric techniques, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) plays a key role as a powerful and sensitive microanalytical technique enabling multi- element trace analysis and isotope ratio measurements at trace and ultratrace level. LA-ICP-MS was used to produce images of detailed regionally-specific element distribution in 20 microm thin sections of different parts of the human brain. The quantitative determination of copper, zinc, lead and uranium distribution in thin slices of human brain samples was performed using matrix-matched laboratory standards via external calibration procedures. Imaging mass spectrometry provides new information on the spatially inhomogeneous element distribution in thin sections of human tissues, for example, of different brain regions (the insular region) or brain tumor tissues. The detection limits obtained for Cu, Zn, Pb and U were in the ng g(-1) range. Possible strategies of LA-ICP-MS in brain research and life sciences include the elemental imaging of thin slices of brain tissue or applications in proteome analysis by combination with matrix-assisted laser desorption/ionization MS to study phospho- and metal- containing proteins will be discussed. PMID:17885277

  5. Determination of selenium urinary metabolites by high temperature liquid chromatography-inductively coupled plasma mass spectrometry.

    PubMed

    Terol, A; Ardini, F; Basso, A; Grotti, M

    2015-02-01

    The coupling of high temperature liquid chromatography (HTLC) and inductively coupled plasma mass spectrometry (ICPMS) for the determination of selenium metabolites in urine samples is reported for the first time. In order to achieve "ICPMS-friendly" chromatographic conditions, the retention on a graphite stationary phase of the major selenium urinary metabolites using only plain water with 2% methanol as the mobile phase was investigated. Under the optimal conditions (T=80°C, Ql=1.2 mL min(-1)), methyl 2-acetamido-2-deoxy-1-seleno-β-d-galactopyranoside (selenosugar 1), methyl 2-acetamido-2-deoxy-1-seleno-β-d-glucosopyranoside (selenosugar 2) and trimethylselenonium ion were efficiently separated in less than 7 min, without any interferences due to other common selenium species (selenite, selenate, selenocystine and selenomethionine) or detectable effect of the urine matrix. The limits of detection were 0.3-0.5 ng Se mL(-1), and the precision of the analytical procedure was better than 3% (RSD%, n=5). The HTLC-ICPMS method was applied to the analysis of urine samples from two volunteers before and after ingestion of Brazil nuts or selenium supplements. The developed procedure proved to be adequate for the analytical task, providing results consistent with previous studies. PMID:25582485

  6. A tightly coupled non-equilibrium model for inductively coupled radio-frequency plasmas

    SciTech Connect

    Munafò, A. Alfuhaid, S. A. Panesi, M.; Cambier, J.-L.

    2015-10-07

    The objective of the present work is the development of a tightly coupled magneto-hydrodynamic model for inductively coupled radio-frequency plasmas. Non Local Thermodynamic Equilibrium (NLTE) effects are described based on a hybrid State-to-State approach. A multi-temperature formulation is used to account for thermal non-equilibrium between translation of heavy-particles and vibration of molecules. Excited electronic states of atoms are instead treated as separate pseudo-species, allowing for non-Boltzmann distributions of their populations. Free-electrons are assumed Maxwellian at their own temperature. The governing equations for the electro-magnetic field and the gas properties (e.g., chemical composition and temperatures) are written as a coupled system of time-dependent conservation laws. Steady-state solutions are obtained by means of an implicit Finite Volume method. The results obtained in both LTE and NLTE conditions over a broad spectrum of operating conditions demonstrate the robustness of the proposed coupled numerical method. The analysis of chemical composition and temperature distributions along the torch radius shows that: (i) the use of the LTE assumption may lead to an inaccurate prediction of the thermo-chemical state of the gas, and (ii) non-equilibrium phenomena play a significant role close the walls, due to the combined effects of Ohmic heating and macroscopic gradients.

  7. A tightly coupled non-equilibrium model for inductively coupled radio-frequency plasmas

    NASA Astrophysics Data System (ADS)

    Munafò, A.; Alfuhaid, S. A.; Cambier, J.-L.; Panesi, M.

    2015-10-01

    The objective of the present work is the development of a tightly coupled magneto-hydrodynamic model for inductively coupled radio-frequency plasmas. Non Local Thermodynamic Equilibrium (NLTE) effects are described based on a hybrid State-to-State approach. A multi-temperature formulation is used to account for thermal non-equilibrium between translation of heavy-particles and vibration of molecules. Excited electronic states of atoms are instead treated as separate pseudo-species, allowing for non-Boltzmann distributions of their populations. Free-electrons are assumed Maxwellian at their own temperature. The governing equations for the electro-magnetic field and the gas properties (e.g., chemical composition and temperatures) are written as a coupled system of time-dependent conservation laws. Steady-state solutions are obtained by means of an implicit Finite Volume method. The results obtained in both LTE and NLTE conditions over a broad spectrum of operating conditions demonstrate the robustness of the proposed coupled numerical method. The analysis of chemical composition and temperature distributions along the torch radius shows that: (i) the use of the LTE assumption may lead to an inaccurate prediction of the thermo-chemical state of the gas, and (ii) non-equilibrium phenomena play a significant role close the walls, due to the combined effects of Ohmic heating and macroscopic gradients.

  8. Direct solid sampling of fire assay beads by spark ablation inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Van Hoven, R. L.; Nam, Sang-Ho; Montaser, Akbar; Doughten, M. W.; Dorrzapf, A. F.

    1995-06-01

    A spark-based, solid-sampling cell is described for inductively coupled plasma mass spectrometry (ICP-MS). The cell is devised for the direct sampling of gold and silver beads produced by the classical lead fire assay procedure. The sampler produces a solid aerosol composed of submicron-sized vapor condensates and small (< 2 μm) spherules. In contrast to solution nebulization, the mass spectrum for spark-ICP-MS is relatively free of interfering metal oxide, polyatomic, and multiply-charged ions. The measurement precision is 3% RSD for Pt, Pd, and Rh preconcentrated into fire assay beads, but is 6% RSD for Ir due to its heterogeneous distribution in a silver bead. Detection limits determined for Pt, Pd, Rh, and Ir in fire assay beads range from 0.6 μg/g (Pt) to 1.2 μg/g (Pd). Calibration curves for these elements are linear up to the highest concentration in the bead studied (2000 μg/g). The quantitative potential of the method is evaluated using the South African Reference Material (SARM-7) geologic standard.

  9. Characterization of natural water resources in Israel by inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Halicz, L.; Becker, J. S.; Pickhardt, C.; Gavrieli, I.; Burg, A.; Nishri, A.; Platzner, I. T.

    2006-03-01

    Analytical procedures are applied for the determination of plutonium, uranium and strontium concentration, their isotope ratios and the analysis of rare earth elements (REE) at trace and ultratrace level in natural Israeli water resources with relatively high matrix content (Na = 20-150 mg L-1, Mg = 20-50 mg L-1 and Ca = 40-100 mg L-1) by inductively coupled plasma mass spectrometry (ICP-MS). To avoid matrix and clogging effects on the cones during mass spectrometric measurements and to analyze Pu and REE at extremely low concentration levels, separation procedures from matrices were applied. An extremely low Pu contamination of the Sea of Galilee was observed due to global nuclear fallout after the nuclear weapons test in the 1960s. The detection limit, for example, for 239Pu was found to be <10-19 g mL-1. For uranium a natural variation of the 234U/238U isotope ratios by a factor of up to 2 in comparison to the IUPAC table value was detected using ICP-MS. This paper discusses the application of double-focusing sector field ICP-MS with single and multiple ion collection as well as quadrupole-based ICP-MS (ICP-QMS) for the quantitative determination of REE, plutonium, uranium and strontium and their isotope ratios after analyte/matrix separation at trace and ultratrace levels in natural water.

  10. Studies of selenium and xenon in inductively coupled plasma mass spectrometry

    SciTech Connect

    Bricker, T.

    1994-07-27

    Since its development, inductively coupled plasma mass spectrometry (ICP-MS) has been a widely used analytical technique. ICP-MS offers low detection limits, easy determination of isotope ratios, and simple mass spectra from analyte elements. ICP-MS has been successfully employed for many applications including geological, environmental, biological, metallurgical, food, medical, and industrial. One specific application important to many areas of study involves elemental speciation by using ICP-MS as an element specific detector interfaced to liquid chromatography. Elemental speciation information is important and cannot be obtained by atomic spectrometric methods alone which measure only the total concentration of the element present. Part 1 of this study describes the speciation of selenium in human serum by size exclusion chromatography (SEC) and detection by ICP-MS. Although ICP-MS has been widely sued, room for improvement still exists. Difficulties in ICP-MS include noise in the background, matrix effects, clogging of the sampling orifice with deposited solids, and spectral interference caused by polyatomic ions. Previous work has shown that the addition of xenon into the central channel of the ICP decreases polyatomic ion levels. In Part 2 of this work, a fundamental study involving the measurement of the excitation temperature is carried out to further understand xenon`s role in the reduction of polyatomic ions. 155 refs.

  11. Determination of rare earth elements in environmental materials by inductively coupled plasma mass spectrometry

    SciTech Connect

    Panday, V.K.; Hoppstock, K.; Becker, J.S.; Dietze, H.J.

    1996-09-01

    Despite the fact that rare earth elements (REE) have found increasing use in modern technology only few data are available on their concentrations in biological and environmental samples. Inductively coupled plasma mass spectrometry (ICP-MS) has been employed to study the concentration of rare earth elements (REE) in various environmental materials (e.g., pine needles, mussel tissue, apple leaves) available from National Institute of Standards and Technology (NIST), the Bureau of European Communities (BCR), and the German Environmental Specimens Bank. After the decomposition of the environmental samples with HNO{sub 3}, the REE (present mostly in the ng/g-range) were separated from the matrix and simultaneously preconcentrated using liquid-liquid extraction with bis(2-ethyl hexyl)-ortho-phosphoric acid (HDEHP) in toluene as a selective reagent at pH = 2 and subsequent back extraction of the elements into the aqueous by 6M HNO{sub 3}. Recoveries of better 90% were obtained for almost all REE. A Perkin Elmer/Sciex ELAN 5000 ICP-MS and HR-ICP-MS ELEMENT from Finnigan MAT were used for quantitative analysis (by external calibration and ID-ICP-MS) of REE. The results of determination of REE concentrations agree well with the data available on some of these materials. Further supplement information on the contents of various REE in these materials.

  12. Studying Arsenite-Humic Acid Complexation Using Size Exclusion Chromatography-Inductively Coupled Plasma Mass Spectrometry

    PubMed Central

    Liu, Guangliang; Cai, Yong

    2012-01-01

    Arsenic (As) can form complexes with dissolved organic matter (DOM), which affects the fate of arsenic in waste sites and natural environments. It remains a challenge to analyze DOM-bound As, in particular by using a direct chromatographic separation method. Size exclusion chromatography (SEC) hyphenated with UV spectrophotometer and inductively coupled plasma mass spectrometry (ICP-MS) was developed to characterize the complexation of arsenite (AsIII) with DOM. This SEC-UV-ICP-MS method is able to differentiate AsIII-DOM complexes from free As species and has the advantage of direct determination of both free and DOM-bound AsIII through mild separation. The suitability of this method for studying AsIII-DOM complexation was demonstrated by its application, in combination with the Scatchard plot and nonlinear regression of ligand binding model, for characterizing AsIII complexation with humic acid (HA) in the absence or presence of natural sand. The results suggest that, consistent with polyelectrolytic nature of HA, the AsIII-HA complexation should be accounted for by multiple classes of binding sites. By loosely classifying the binding sites into strong (S1) and weak (S2) sites, the apparent stability constants (Ks) of the resulting As-DOM complexes were calculated as log Ks1 = 6.5–7.1 while log Ks2 = 4.7–5.0. PMID:22664255

  13. The survival of gunshot residues in cremated bone: an inductively coupled plasma optical emission spectrometry study.

    PubMed

    Amadasi, Alberto; Merli, Daniele; Brandone, Alberto; Poppa, Pasquale; Gibelli, Daniele; Cattaneo, Cristina

    2013-07-01

    Gunshot residue (GSR) has been sought and demonstrated on many types of material and with many techniques. Inductively coupled plasma optical emission spectrometry (ICP-OES) could be a useful method on difficult substrates, but a systematic study on burnt material has never been performed. Hence, this study aims at evaluating the usefulness and reliability of this method on burnt samples. Sixteen adult bovine ribs (eight with soft tissues, eight totally skeletonized) were shot using two kinds of projectile (both 9 mm full metal-jacketed or unjacketed). Then, every sample was led to complete calcination in an electric oven. The area of the gunshot entrance wound was swabbed and analyzed by ICP-OES; the results were also correlated with a previously published parallel study by scanning electron microscopy (SEM) equipped with an SEM-energy dispersive X-ray analyzer. ICP-OES proved to be very sensitive and reliable even on degraded material and can be an appropriate nondestructive method for detecting residues on difficult and delicate substrates such as burnt bone. PMID:23692414

  14. Testing of Diode-Clamping in an Inductive Pulsed Plasma Thruster Circuit

    NASA Technical Reports Server (NTRS)

    Toftul, Alexandra; Polzin, Kurt A.; Martin, Adam K.; Hudgins, Jerry L.

    2014-01-01

    Testing of a 5.5 kV silicon (Si) diode and 5.8 kV prototype silicon carbide (SiC) diode in an inductive pulsed plasma thruster (IPPT) circuit was performed to obtain a comparison of the resulting circuit recapture efficiency,eta(sub r), defined as the percentage of the initial charge energy remaining on the capacitor bank after the diode interrupts the current. The diode was placed in a pulsed circuit in series with a silicon controlled rectifier (SCR) switch, and the voltages across different components and current waveforms were collected over a range of capacitor charge voltages. Reverse recovery parameters, including turn-off time and peak reverse recovery current, were measured and capacitor voltage waveforms were used to determine the recapture efficiency for each case. The Si fast recovery diode in the circuit was shown to yield a recapture efficiency of up to 20% for the conditions tested, while the SiC diode further increased recapture efficiency to nearly 30%. The data presented show that fast recovery diodes operate on a timescale that permits them to clamp the discharge quickly after the first half cycle, supporting the idea that diode-clamping in IPPT circuit reduces energy dissipation that occurs after the first half cycle

  15. 200-mm-diameter neutral beam source based on inductively coupled plasma etcher and silicon etching

    SciTech Connect

    Kubota, Tomohiro; Nukaga, Osamu; Ueki, Shinji; Sugiyama, Masakazu; Inamoto, Yoshimasa; Ohtake, Hiroto; Samukawa, Seiji

    2010-09-15

    The authors developed a neutral beam source consisting of a 200-mm-diameter inductively coupled plasma etcher and a graphite neutralization aperture plate based on the design of a neutral beam source that Samukawa et al. [Jpn. J. Appl. Phys., Part 2 40, L779 (2001)] developed. They measured flux and energy of neutral particles, ions, and photons using a silicon wafer with a thermocouple and a Faraday cup and calculated the neutralization efficiency. An Ar neutral beam flux of more than 1 mA/cm{sup 2} in equivalent current density and a neutralization efficiency of more than 99% were obtained. The spatial uniformity of the neutral beam flux was within {+-}6% within a 100 mm diameter. Silicon etching using a F{sub 2}-based neutral beam was done at an etch rate of about 47 nm/min, while Cl{sub 2}-based neutral beam realized completely no undercut. The uniformity of etch rate was less than {+-}5% within the area. The etch rate increased by applying bias power to the neutralization aperture plate, which shows that accelerated neutral beam was successfully obtained. These results indicate that the neutral beam source is scalable, making it possible to obtain a large-diameter and uniform neutral beam, which is inevitable for application to mass production.

  16. Improving sensitivity for microchip electrophoresis interfaced with inductively coupled plasma mass spectrometry using parallel multichannel separation.

    PubMed

    Cheng, Heyong; Liu, Jinhua; Xu, Zigang; Wang, Yuanchao; Ye, Meiying

    2016-08-26

    We reported sensitivity enhancement using multichannel parallel separation for microchip electrophoresis hyphenated with inductively coupled plasma mass spectrometry (MCE-ICP-MS) in this study. By using 2-20 array lanes for parallel separation, the sensitivity of the MCE-ICP-MS system was proportionally improved by 2-20 folds. No significantly adverse effect of parallel separation on column efficiency and resolution was observed. Rapid separation of Hg(2+) and methylmercuric (MeHg) ion within 36s under an electric field of 800Vcm(-1) was achieved in the 2-cm twenty-channels with a background electrolyte of 5mmolL(-1) borate buffer (pH 9.2). Detection limits of Hg(2+) and MeHg by the proposed system were decreased to 6.8-7.1ngL(-1). Good agreement between determined values and certified values of a certified reference fish was obtained with recoveries ranged between 94-98%. All results prove its advantages including high sensitivity, high efficiency and low operation cost, which are beneficial to routine analysis of metal speciation in environmental, biological and food fields. PMID:27488720

  17. Heteroepitaxial growth of wafer scale highly oriented graphene using inductively coupled plasma chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Gao, Libo; Xu, Hai; Li, Linjun; Yang, Yang; Fu, Qiang; Bao, Xinhe; Loh, Kian Ping

    2016-06-01

    The chemical vapor deposition (CVD) of graphene on Cu has attracted much attention because of its industrial scalability. Herein, we report inductively coupled plasma-assisted CVD of epitaxially grown graphene on (111)-textured Cu film alloyed with a small amount of Ni, where large area high quality graphene film can be grown in less than 5 min at 800 °C, thus affording industrial scalability. The epitaxially grown graphene films on (111)-textured Cu contain grains which are predominantly aligned with the Cu lattice and about 10% of 30°-rotated grains (anti-grains). Such graphene films are exclusively monolayer and possess good electrical conductivity, high carrier mobility, and room temperature quantum Hall effect. Magnetoresistance measurements reveal that the reduction of the grain sizes from 150 nm to 50 nm produce increasing Anderson localization and the appearance of a transport gap. Owing to the presence of grain boundaries in these anti-grains, epitaxially grown graphene films possess n-type characteristics and exhibit ultra-high sensitivity to adsorbates.

  18. Nanocrystalline silicon embedded in silicon suboxide synthesized in high-density inductively coupled plasma

    NASA Astrophysics Data System (ADS)

    Zhou, H. P.; Xu, S.; Xu, M.; Xiao, S. Q.; Xiang, Y.

    2015-11-01

    A two-phase material system of nanocrystalline silicon (nc-Si) embedded in a dielectric matrix of silicon suboxide (SiO x ) is fundamentally and technologically significant for the photonic and photovoltaic device such as light emission diode and solar cells. nc-Si in amorphous SiO x has been synthesized by means of the low-frequency (460 kHz) inductively coupled plasma (LFICP) of SiH4  +  CO2  +  H2 without the common route of high hydrogen dilution. The chemical composition, microstructures and optical properties of the complex material system are tuned by the reactive gas flow rate ratio of CO2/SiH4. nc-Si embedded in amorphous SiO x due to the phase separation are observed by means of SEM and TEM characterization tools. The crystalline volume fraction in nc-SiO x :H is determined by the density of the embedded nc-Si particles and the occurrence of the a-SiO x encapsulating shell layer. The bond configuration analysis shows the concurrent oxygenation and dehydrogenation process with the incorporation of oxygen. The underlying mechanism in forming the two-phase complex material system and the phase evolution with the reactive gas flow rate ratio are discussed in terms of the unique features of the utilized high-density LFICP.

  19. Analysis of fertilizers for major, micro, and trace elements by inductively coupled plasma emission spectroscopy

    NASA Astrophysics Data System (ADS)

    Jones, J. B., Jr.

    The concentrations of nine elements (B, Ca, Cu, Fe, K, Mg, Mn, P, and Zn) in 34 Magruder Fertilizer Standards were determined by inductively coupled plasma (ICP) emission spectroscopy, and the results compared favorably with the known concentrations for all the elements. In addition to these nine fertilizer elements, six others (AI, Cd, Cr, Na, Ni, and Pb) were determined in the same analysis, although results could only be compared to similar analyses made by two other laboratories employing ICP. All 15 elements were also determined in 12 spent acids used to manufacture liquid fertilizer and analysis results compared among the three laboratories. Analysis by ICP spectroscopy of fertilizer materials with wide ranges of elemental contents was found to be a rapid analysis technique which can give comparable results with those obtained by the more laborious AOAC procedures as well as the opportunity to determine other than only the important fertilizer elements. Collaborative study is recommended for ICP determination of the elements of importance in fertilizers for adaptation of the ICP technique by the Association of Official Analytical Chemists.

  20. Sulfur analysis by inductively coupled plasma-mass spectrometry: A review

    NASA Astrophysics Data System (ADS)

    Giner Martínez-Sierra, J.; Galilea San Blas, O.; Marchante Gayón, J. M.; García Alonso, J. I.

    2015-06-01

    In recent years the number of applications of sulfur (S) analysis using inductively coupled plasma mass spectrometry (ICP-MS) as detector has increased significantly. In this article we describe in some depth the application of ICP-MS for S analysis with emphasis placed on the sulfur-specific detection by hyphenated techniques such as LC, GC, CE and LA coupled on-line to ICP-MS. The different approaches available for sulfur isotope ratio measurements by ICP-MS are also detailed. Particular attention has been paid to the quantification of peptides/proteins and the analysis of metallopeptides/metalloproteins via sulfur by LC-ICP-MS. Likewise, the speciation analysis of metal-based pharmaceuticals and metallodrugs and non-metal selective detection of pharmaceuticals via S are highlighted. Labeling procedures for metabolic applications are also included. Finally, the measurement of natural variations in S isotope composition with multicollector ICP-MS instruments is also covered in this review.

  1. Laser ablation inductively coupled plasma mass spectrometry imaging of metals in experimental and clinical Wilson's disease

    PubMed Central

    Boaru, Sorina Georgiana; Merle, Uta; Uerlings, Ricarda; Zimmermann, Astrid; Flechtenmacher, Christa; Willheim, Claudia; Eder, Elisabeth; Ferenci, Peter; Stremmel, Wolfgang; Weiskirchen, Ralf

    2015-01-01

    Wilson's disease is an autosomal recessive disorder in which the liver does not properly release copper into bile, resulting in prominent copper accumulation in various tissues. Affected patients suffer from hepatic disorders and severe neurological defects. Experimental studies in mutant mice in which the copper-transporting ATPase gene (Atp7b) is disrupted revealed a drastic, time-dependent accumulation of hepatic copper that is accompanied by formation of regenerative nodes resembling cirrhosis. Therefore, these mice represent an excellent exploratory model for Wilson's disease. However, the precise time course in hepatic copper accumulation and its impact on other trace metals within the liver is yet poorly understood. We have recently established novel laser ablation inductively coupled plasma mass spectrometry protocols allowing quantitative metal imaging in human and murine liver tissue with high sensitivity, spatial resolution, specificity and quantification ability. By use of these techniques, we here aimed to comparatively analyse hepatic metal content in wild-type and Atp7b deficient mice during ageing. We demonstrate that the age-dependent accumulation of hepatic copper is strictly associated with a simultaneous increase in iron and zinc, while the intrahepatic concentration and distribution of other metals or metalloids is not affected. The same findings were obtained in well-defined human liver samples that were obtained from patients suffering from Wilson's disease. We conclude that in Wilson's disease the imbalances of hepatic copper during ageing are closely correlated with alterations in intrahepatic iron and zinc content. PMID:25704483

  2. Elemental Bioimaging by Means of Fast Scanning Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry.

    PubMed

    Wehe, Christoph A; Thyssen, Georgina M; Herdering, Christina; Raj, Indra; Ciarimboli, Giuliano; Sperling, Michael; Karst, Uwe

    2015-08-01

    One of the most common setups for elemental bioimaging, the hyphenation of a laser ablation (LA) system and an inductively coupled plasma mass spectrometer (ICP-MS), was expanded by adding full scan mass spectrometric information as another dimension of information. While most studies deal with the analysis of typically not more than up to 10 isotopes per scan cycle, a fast scanning quadrupole mass analyzer was utilized to record the full mass spectrum of interest in this work. Mass-to-charge ratios from 6 to 250 were observed within one cycle. Besides the x- and y-position on the ablated sample and the intensity, the m/z-ratio served as fourth variable for each pixel of the obtained data, closing thereby the gap between "inorganic" and "organic" mass spectrometric imaging techniques. The benefits of this approach include an improved control of interferences, the discovery of unexpected elemental distributions, the possibility to plot isotopic ratios, and to integrate the intensities of a certain number of mass channels recorded for each isotope, thus virtually increasing sensitivity. The respective data are presented for dried droplets as well as embedded animal and human tissue slices. Limits of detection were calculated and found to be in accordance with counting statistics. A dedicated software macro was developed for data manipulation prior to common evaluation and image creation. PMID:25947196

  3. Internal plasma potential measurements of a Hall thruster using plasma lens focusing

    SciTech Connect

    Linnell, Jesse A.; Gallimore, Alec D.

    2006-10-15

    Magnetic field topology has been found to be a central design concern for high-efficiency Hall thrusters. For future improvements in Hall thruster design, it is necessary to better understand the effects that magnetic field topology has on the internal plasma structure. The Plasmadynamics and Electric Propulsion Laboratory's High-speed Axial Reciprocating Probe system is used in conjunction with a floating emissive probe to map the internal plasma potential structure of the NASA-173Mv1 Hall thruster [R. R. Hofer, R. S. Jankovsky, and A. D. Gallimore, J. Propul. Power 22, 721 (2006); 22, 732 (2006)]. Measurements are taken at 300 and 500 V with a xenon propellant. Electron temperature and electric field are also measured and reported. The acceleration zone and equipotential lines are found to be strongly linked to the magnetic field lines. Moreover, in some cases the ions are accelerated strongly toward the center of the discharge channel. The agreement between magnetic field lines and equipotential lines is best for high-voltage operation. These results have strong implications on the performance and lifetime optimization of Hall thrusters.

  4. Non-invasive in situ plasma monitoring of reactive gases using the floating harmonic method for inductively coupled plasma etching application

    SciTech Connect

    Lee, J. H.; Kim, M. J.; Yoon, Y. S.

    2013-04-15

    The floating harmonic method was developed for in situ plasma diagnostics of allowing real time measurement of electron temperature (T{sub e}) and ion flux (J{sub ion}) without contamination of the probe from surface modification by reactive species. In this study, this novel non-invasive diagnostic system was studied to characterize inductively coupled plasma of reactive gases monitoring T{sub e} and J{sub ion} for investigating the optimum plasma etching conditions and controlling of the real-time plasma surface reaction in the range of 200-900 W source power, 10-100 W bias power, and 3-15 mTorr chamber pressure, respectively.

  5. Access to high beta advanced inductive plasmas at low injected torque

    NASA Astrophysics Data System (ADS)

    Solomon, W. M.; Politzer, P. A.; Buttery, R. J.; Holcomb, C. T.; Ferron, J. R.; Garofalo, A. M.; Grierson, B. A.; Hanson, J. M.; In, Y.; Jackson, G. L.; Kinsey, J. E.; La Haye, R. J.; Lanctot, M. J.; Luce, T. C.; Okabayashi, M.; Petty, C. C.; Turco, F.; Welander, A. S.

    2013-09-01

    Recent experiments on DIII-D demonstrate that advanced inductive (AI) discharges with high equivalent normalized fusion gain can be accessed and sustained with very low amounts (∼1 N m) of externally injected torque, a level of torque that is anticipated to drive a similar amount of rotation as the beams on ITER, via simple consideration of the scaling of the moment of inertia and confinement time. The AI regime is typically characterized by high confinement, and high βN, allowing the possibility for high performance, high gain operation at reduced plasma current. Discharges achieved βN ∼ 3.1 with H98(y,2) ∼ 1 at q95 ∼ 4, and are sustained for the maximum duration of the counter neutral beams (NBs). In addition, plasmas using zero net NB torque from the startup all the way through to the high βN phase have been created. AI discharges are found to become increasingly susceptible to m/n = 2/1 neoclassical tearing modes as the torque is decreased, which if left unmitigated, generally slow and lock, terminating the high performance phase of the discharge. Access is not notably different whether one ramps the torque down at high βN, or ramps βN up at low torque. The use of electron cyclotron heating (ECH) and current drive proved to be an effective method of avoiding such modes, enabling stable operation at high beta and low torque, a portion of phase space that has otherwise been inaccessible. Thermal confinement is significantly reduced at low rotation, a result that is reproduced using the TGLF transport model. Although it is thought that stiffness is increased in regions of low magnetic shear, in these AI plasmas, the reduced confinement occurs at radii outside the low shear, and in fact, higher temperature gradients can be found in the low shear region at low rotation. Momentum transport is also larger at low rotation, but a significant intrinsic torque is measured that is consistent with a previous scaling considering the role of the turbulent

  6. High density plasma etching of ultrananocrystalline diamond films in O2/CF4 and O2/SF6 inductively coupled plasmas

    NASA Astrophysics Data System (ADS)

    Park, Jong Cheon; Kim, Seong Hak; Kim, Tae Gyu; Kim, Jin Kon; Cho, Hyun; Lee, Byeong Woo

    2015-03-01

    Inductively coupled plasma etching of ultrananocrystalline diamond (UNCD) films was performed in O2/CF4 and O2/SF6 discharges. Higher etch rates were produced for the O2/SF6 discharges and the films etched in the 10O2/5CF4 discharges retained smooth surface morphology similar to the unetched control sample. Al mask showed a good etch selectivity to the UNCD for both plasma chemistries and highly anisotropic pattern transfer with a vertical sidewall profile was achieved.

  7. A study of the relation between the limit of detection and the limit of quantitation in inductively coupled plasma spectrochemistry

    NASA Astrophysics Data System (ADS)

    Carré, M.; Excoffier, S.; Mermet, J. M.

    1997-12-01

    The limit of quantitation based on a repeatability threshold concept is compared with the limit of detection in induction coupled plasma atomic emission spectrometry (ICP-AES) and induction coupled plasma mass spectrometry (ICP-MS). A 5%-based limit of quantitation would normally correspond to 10 times the 3-σ based limit of detection. However, because of a possible lack of linearity of the calibration graph at low concentrations, some additional noise not taken into consideration and the possible use of time-correlated multichannel detection, this ratio of 10 cannot be used in every case. It is suggested that a suitable way of determining the limit of quantitation is to establish the plot of the percentage relative standard deviation (RSD) of the net signal as a function of the concentration in a range from the limit of detection to 50 times this limit.

  8. Fractionation analysis of manganese in Turkish hazelnuts (Corylus avellana L.) by inductively coupled plasma-mass spectrometry.

    PubMed

    Erdemir, Umran Seven; Gucer, Seref

    2014-11-01

    In this study, an analytical fractionation scheme based on water, diethyl ether, n-hexane, and methanol extractions has been developed to identify manganese-bound fractions. Additionally, in vitro simulated gastric and intestinal digestion, n-octanol extraction, and activated carbon adsorption were used to interpret the manganese-bound structures in hazelnuts in terms of bioaccessibility. The total content of manganese in the samples was determined by inductively coupled plasma-mass spectrometry after microwave-assisted digestion, and additional validation was performed using atomic absorption spectroscopy. Water fractions were further evaluated by high-performance liquid chromatography hyphenated to inductively coupled plasma-mass spectrometry for the identification of water-soluble manganese fractions in hazelnut samples. The limits of detection and quantification were 3.6 and 12.0 μg L(-1), respectively, based on peak height. PMID:25310841

  9. Determination of arsenic in gold by flow injection inductively coupled plasma mass spectrometry with matrix removal by reductive precipitation

    NASA Astrophysics Data System (ADS)

    Becotte-Haigh, Paul; Tyson, Julian F.; Denoyer, Eric; Hinds, Michael W.

    1996-12-01

    Arsenic was determined in gold by flow injection hydride generation inductively coupled plasma-mass spectrometry following a batch mode reductive precipitation removal of the interfering gold matrix. A solution of potassium iodide, L-ascorbic acid, and hydrochloric acid was used as the reluctant. The recovery of gold by precipitation and filtration was 99 ± 3%. The detection limit for arsenic in gold was 55 ng g -1 in the solid. The concentration of arsenic that was determined in the Royal Canadian Mint gold sample FAU-10 was 29.7 μg g -1 in the solid; this value was indistinguishable, with 95% confidence, from values determined at the Royal Canadian Mint by graphite furnace atomic absorption spectrometry and by inductively coupled plasma-mass spectrometry. The standard deviation for four replicate determinations of the arsenic in FAU-10 was 0.972 μg g -1 in the solid.

  10. Ionosphere Plasma State Determination in Low Earth Orbit from International Space Station Plasma Monitor

    NASA Technical Reports Server (NTRS)

    Kramer, Leonard

    2014-01-01

    A plasma diagnostic package is deployed on the International Space Station (ISS). The system - a Floating Potential Measurement Unit (FPMU) - is used by NASA to monitor the electrical floating potential of the vehicle to assure astronaut safety during extravehicular activity. However, data from the unit also reflects the ionosphere state and seems to represent an unutilized scientific resource in the form of an archive of scientific plasma state data. The unit comprises a Floating Potential probe and two Langmuir probes. There is also an unused but active plasma impedance probe. The data, at one second cadence, are collected, typically for a two week period surrounding extravehicular activity events. Data is also collected any time a visiting vehicle docks with ISS and also when any large solar events occur. The telemetry system is unusual because the package is mounted on a television camera stanchion and its data is impressed on a video signal that is transmitted to the ground and streamed by internet to two off center laboratory locations. The data quality has in the past been challenged by weaknesses in the integrated ground station and distribution systems. These issues, since mid-2010, have been largely resolved and the ground stations have been upgraded. Downstream data reduction has been developed using physics based modeling of the electron and ion collecting character in the plasma. Recursive algorithms determine plasma density and temperature from the raw Langmuir probe current voltage sweeps and this is made available in real time for situational awareness. The purpose of this paper is to describe and record the algorithm for data reduction and to show that the Floating probe and Langmuir probes are capable of providing long term plasma state measurement in the ionosphere. Geophysical features such as the Appleton anomaly and high latitude modulation at the edge of the Auroral zones are regularly observed in the nearly circular, 51 deg inclined, 400 km

  11. Optimization of determination of platinum group elements in airborne particulate matter by inductively coupled plasma mass spectrometry.

    PubMed

    Bujdoš, Marek; Hagarová, Ingrid; Matúš, Peter; Canecká, Lucia; Kubová, Jana

    2012-03-01

    Determination of automotive traffic-emitted platinum group metals (PGM) by inductively coupled plasma quadrupole mass spectrometry (ICP-MS) was optimized. The interferences from Sr, Cu, Pb, Y, Cd, Zr and Hf were evaluated using model solutions. Plasma radiofrequency (RF) power and nebulizer gas flow were optimized for 103Rh, 105Pd, 108Pd and 195Pt. Two standard reference materials were analyzed: SARM-7 Platinum ore and BCR-723 Road dust. The optimized procedure was used to analyze samples of airborne particulate matter collected in the urban site with heavy automotive traffic in the centre of Bratislava, Slovakia. PMID:24061181

  12. Novel strategy for a bispecific antibody: induction of dual target internalization and degradation.

    PubMed

    Lee, J M; Lee, S H; Hwang, J-W; Oh, S J; Kim, B; Jung, S; Shim, S-H; Lin, P W; Lee, S B; Cho, M-Y; Koh, Y J; Kim, S Y; Ahn, S; Lee, J; Kim, K-M; Cheong, K H; Choi, J; Kim, K-A

    2016-08-25

    Activation of the extensive cross-talk among the receptor tyrosine kinases (RTKs), particularly ErbB family-Met cross-talk, has emerged as a likely source of drug resistance. Notwithstanding brilliant successes were attained while using small-molecule inhibitors or antibody therapeutics against specific RTKs in multiple cancers over recent decades, a high recurrence rate remains unsolved in patients treated with these targeted inhibitors. It is well aligned with multifaceted properties of cancer and cross-talk and convergence of signaling pathways of RTKs. Thereby many therapeutic interventions have been actively developed to overcome inherent or acquired resistance. To date, no bispecific antibody (BsAb) showed complete depletion of dual RTKs from the plasma membrane and efficient dual degradation. In this manuscript, we report the first findings of a target-specific dual internalization and degradation of membrane RTKs induced by designed BsAbs based on the internalizing monoclonal antibodies and the therapeutic values of these BsAbs. Leveraging the anti-Met mAb able to internalize and degrade by a unique mechanism, we generated the BsAbs for Met/epidermal growth factor receptor (EGFR) and Met/HER2 to induce an efficient EGFR or HER2 internalization and degradation in the presence of Met that is frequently overexpressed in the invasive tumors and involved in the resistance against EGFR- or HER2-targeted therapies. We found that Met/EGFR BsAb ME22S induces dissociation of the Met-EGFR complex from Hsp90, followed by significant degradation of Met and EGFR. By employing patient-derived tumor models we demonstrate therapeutic potential of the BsAb-mediated dual degradation in various cancers. PMID:26853467

  13. A hybrid model in inductively coupled plasma discharges with bias source: Description of model and experimental validation in Ar discharge

    NASA Astrophysics Data System (ADS)

    Wen, De-Qi; Liu, Wei; Liu, Yong-Xin; Gao, Fei; Wang, You-Nian

    2015-09-01

    Traditional fluid simulation and Particle-in-Cell/Monte-Carlo collision (PIC/MCC) are very time consuming in inductively coupled plasma. In this work, a hybrid model, i.e. global model coupled bidirectional with parallel Monte-Carlo collision (MCC) sheath model, is developed to investigate inductively coupled plasma discharge with bias source. The global model is applied to calculate plasma density in bulk plasma. The sheath model is performed to consistently calculate the electric field, ion kinetic and the sheath thickness above the bias electrode. Moreover, specific numbers of ions are tracked and ultimately ion energy distribution functions (IEDFs) incident into bias electrode are obtained from MCC module. It is found that as the bias amplitude increases, the energy width of both IEDFs becomes wider, and the total outlines of IEDFs move towards higher energy. The results from the model are validated by experimental measurement and a qualitative agreement is obtained. The advantage of this model is that plasma density, ion flux and IEDF, which are widely concerned in the actual process, could be obtained within an hour. This work was supported by the National Natural Science Foundation of China (NSFC) (Grant No. 11205025 and 11335004) and (Grant No.11405018), the Important National Science and Technology Specific Project (Grant No. 2011ZX02403-001).

  14. Determination of Sulfur in High-Level Waste Sludge by Inductively Coupled Plasma-Atomic Emission Spectroscopy and Ion Chromatography

    SciTech Connect

    COLEMAN, CJ

    2004-04-22

    Significant differences (approximately 30 percent) have been observed in the sulfur measurements in high-level waste sludge by the Analytical Development Section (ADS) using the inductively coupled plasma-atomic emission spectroscopy (ICP-AES) method compared with the ADS ion chromatography (IC) method. Since the measured concentrations of sulfur in the sludge approached the maximum concentration that can be processed in the DWPF, experiments were performed to determine the source of the differences and assess the true accuracy of sulfur measurements.

  15. [Determination of trace elements in sika bone powder by inductively coupled plasma mass spectrometry with microwave digestion].

    PubMed

    Liu, Yan-Ming; Chen, Zhi-Yong; Han, Jin-Tu; Wang, Hui; Wang, Zhi-Wen

    2006-05-01

    Contents of trace elements in sika bone powder were determined with microwave digestion and inductively coupled plasma mass spectrometry. Under the optimum conditions, the detection limits (3sigma, n = 11) are in the range of 0. 000 6-1. 498 ng x mL(-1) with relative standard deviations of 1.7%-6.8%. The recoveries are between 91% and 109%. The analytical results of national certified reference demonstrated the applicability of the proposed method. PMID:16883876

  16. Elemental analysis of biological samples by graphite furnace, inductively coupled plasma - atomic emission spectroscopy (GF-ICP-AES)

    SciTech Connect

    Winge, R.K.; Fassel, V.A.; Grabau, F.; Zu-cheng, J.

    1984-08-01

    The large number of analyses required for monitoring environmental pollution and its ecological impacts suggests that an analytical screening method would be very useful if it could rapidly distinguish those samples containing environmentally significant concentrations of pollutants from those that do not. In the trace elemental analysis of solids the most time consuming step is often the conversion of the sample into a suitable analytical form, usually a digestion and dissolution process. We have addressed these problems by combining a graphite furnace with inductively coupled plasma-atomic emission spectroscopy. With this system solid samples of plant and animal tissue, as well as solutions, can be vaporized and introduced directly into the inductively coupled plasma. A simple standard additions technique was developed for solid samples that yielded acceptable results for a number of elements in biological samples. Powers of detection were not satisfactory for the lowest concentrations of several elements in the NBS biological SRMs and analytical uncertainties were relatively high for quantitative analyses but were generally satisfactory for screening methods. The design of the interface between the graphite furnace and the inductively coupled plasma and the pulse effect caused by the vaporization of the sample are critical factors in the GF-ICP-AES method. 31 references, 21 figures, 4 tables.

  17. Automated in situ trace element analysis of silicate materials by laser ablation inductively coupled plasma mass spectrometry.

    PubMed

    Chen, Z; Canil, D; Longerich, H P

    2000-09-01

    This paper describes the automated in situ trace element analysis of solid materials by laser ablation (LA) inductively coupled plasma mass spectrometry (ICP-MS). A compact computer-controlled solid state Nd:YAG Merchantek EO UV laser ablation (LA) system has been coupled with the high sensitivity VG PQII S ICP-MS. A two-directional communication was interfaced in-house between the ICP-MS and the LA via serial RS-232 port. Each LA-ICP-MS analysis at a defined point includes a 60 s pre-ablation delay, a 60 s ablation, and a 90 s flush delay. The execution of each defined time setting by LA was corresponding to the ICP-MS data acquisition allowing samples to be run in automated cycle sequences like solution auto-sampler ICP-MS analysis. Each analytical cycle consists of four standards, one control reference material, and 15 samples, and requires about 70 min. Data produced by Time Resolved Analysis (TRA) from ICP-MS were later reduced off-line by in-house written software. Twenty-two trace elements from four reference materials (NIST SRM 613, and fused glass chips of BCR-2, SY-4, and G-2) were determined by the automated LA-ICP-MS method. NIST SRM 610 or NIST SRM 613 was used as an external calibration standard, and Ca as an internal standard to correct for drift, differences in transport efficiency and sampling yield. Except for Zr and Hf in G-2, relative standard deviations for all other elements are less than 10%. Results compare well with the data reported from literature with average limits of detection from 1 ng x g(-1) to 455 ng x g(-1) and less than 100 ng x g(-1) for most trace elements. PMID:11220835

  18. Determination of rare earth and concomitant elements in magnesium alloys by inductively coupled plasma optical emission spectrometry.

    PubMed

    Fariñas, Juan C; Rucandio, Isabel; Pomares-Alfonso, Mario S; Villanueva-Tagle, Margarita E; Larrea, María T

    2016-07-01

    An Inductively Coupled Plasma Optical Emission Spectrometry method for simultaneous determination of Al, Ca, Cu, Fe, In, Mn, Ni, Si, Sr, Y, Zn, Zr and rare earth elements (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) in magnesium alloys, including the new rare earth elements-alloyed magnesium, has been developed. Robust conditions have been established as nebulizer argon flow rate of 0.5mLmin(-1) and RF incident power of 1500W, in which matrix effects were significantly reduced around 10%. Three acid digestion procedures were performed at 110°C in closed PFA vessels heated in an oven, in closed TFM vessels heated in a microwave furnace, and in open polypropylene tubes with reflux caps heated in a graphite block. The three digestion procedures are suitable to put into solution the magnesium alloys samples. From the most sensitive lines, one analytical line with lack or low spectral interferences has been selected for each element. Mg, Rh and Sc have been studied as internal standards. Among them, Rh was selected as the best one by using Rh I 343.488nm and Rh II 249.078nm lines as a function of the analytical lines. The trueness and precision have been established by using the Certified Reference Material BCS 316, as well as by means of recovery studies. Quantification limits were between 0.1 and 9mgkg(-1) for Lu and Pr, respectively, in a 2gL(-1) magnesium matrix solution. The method developed has been applied to the commercial alloys AM60, AZ80, ZK30, AJ62, WE54 and AE44. PMID:27154648

  19. Precise ruthenium fission product isotopic analysis using dynamic reaction cell inductively coupled plasma mass spectrometry (DRC-ICP-MS)

    SciTech Connect

    Brown, Christopher F.; Dresel, P. Evan; Geiszler, Keith N.; Farmer, Orville T.

    2006-05-09

    99Tc is a subsurface contaminant of interest at numerous federal, industrial, and international facilities. However, as a mono-isotopic fission product, 99Tc lacks the ability to be used as a signature to differentiate between the different waste disposal pathways that could have contributed to subsurface contamination at these facilities. Ruthenium fission-product isotopes are attractive analogues for the characterization of 99Tc sources because of their direct similarity to technetium with regard to subsurface mobility, and their large fission yields and low natural background concentrations. We developed an inductively coupled plasma mass spectrometry (ICP-MS) method capable of measuring ruthenium isotopes in groundwater samples and extracts of vadose zone sediments. Samples were analyzed directly on a Perkin Elmer ELAN DRC II ICP-MS after a single pass through a 1-ml bed volume of Dowex AG 50W-X8 100-200 mesh cation exchange resin. Precise ruthenium isotopic ratio measurements were achieved using a low-flow Meinhard-type nebulizer and long sample acquisition times (150,000 ms). Relative standard deviations of triplicate replicates were maintained at less than 0.5% when the total ruthenium solution concentration was 0.1 ng/ml or higher. Further work was performed to minimize the impact caused by mass interferences using the dynamic reaction cell (DRC) with O2 as the reaction gas. The aqueous concentrations of 96Mo and 96Zr were reduced by more than 99.7% in the reaction cell prior to injection of the sample into the mass analyzer quadrupole. The DRC was used in combination with stable-mass correction to quantitatively analyze samples containing up to 2-orders of magnitude more zirconium and molybdenum than ruthenium. The analytical approach documented herein provides an efficient and cost-effective way to precisely measure ruthenium isotopes and quantitate total ruthenium (natural vs. fission-product) in aqueous matrixes.

  20. Determination of rare earth impurities in high purity samarium oxide using inductively coupled plasma mass spectrometry after extraction chromatographic separation

    NASA Astrophysics Data System (ADS)

    Zhang, Xinquan; Liu, Jinglei; Yi, Yong; Liu, Yonglin; Li, Xiang; Su, Yaqin; Lin, Ping

    2007-01-01

    A method for the determination of trace of 14 rare earth elements (REEs) as impurities in high purity samarium oxide (Sm2O3) using inductively coupled plasma mass spectrometry (ICP-MS) was described. Analytes, such as La, Ce, Pr, Nd, Eu, Gd, Tb, Lu and Y were measured without Sm matrix separation because of no interference problems occurring that could affect the analysis of these elements. On the other hand, analytes, such as Dy, Ho, Er, Tm and Yb were carried out after Sm matrix being eliminated completely by means of 2-ethylhexyl hydrogen-ethylhexy phosphonate (EHEHP) extraction chromatographic separation. The inherent problem associated with matrix-induced suppression was effectively compensated with spiking In as internal standard element and the mass spectra isobaric interferences of atomic and molecular ions arose from Sm matrix had been overcome after the removal of Sm matrix. The limits of quantitations (LOQ) for 14 REEs impurities were from 0.01 to 0.07 [mu]g g-1 together with the recoveries of spiking sample of 14 REEs were found to be in the range of 85-110% and the proposed method precision was less than 5%. A synthetic standard Sm2O3 sample with well-known 14 REEs concentrations was prepared and analysed in order to prove the accuracy and precision of the proposed method together with another high purity Sm2O3 was also measured using ICP-MS. The methodology had been found to be suitable for the determination of trace of 14 REEs in 99.999-99.9999% high purity Sm2O3.

  1. Bulk vertical micromachining of single-crystal sapphire using inductively coupled plasma etching for x-ray resonant cavities

    NASA Astrophysics Data System (ADS)

    Chen, P.-C.; Lin, P.-T.; Mikolas, D. G.; Tsai, Y.-W.; Wang, Y.-L.; Fu, C.-C.; Chang, S.-L.

    2015-01-01

    To provide coherent x-ray sources for probing the dynamic structures of solid or liquid biological substances on the picosecond timescale, a high-aspect-ratio x-ray resonator cavity etched from a single crystal substrate with a nearly vertical sidewall structure is required. Although high-aspect-ratio resonator cavities have been produced in silicon, they suffer from unwanted multiple beam effects. However, this problem can be avoided by using the reduced symmetry of single-crystal sapphire in which x-ray cavities may produce a highly monochromatic transmitted x-ray beam. In this study, we performed nominal 100 µm deep etching and vertical sidewall profiles in single crystal sapphire using inductively coupled plasma (ICP) etching. The large depth is required to intercept a useful fraction of a stopped-down x-ray beam, as well as for beam clearance. An electroplated Ni hard mask was patterned using KMPR 1050 photoresist and contact lithography. The quality and performance of the x-ray cavity depended upon the uniformity of the cavity gap and therefore verticality of the fabricated vertical sidewall. To our knowledge, this is the first report of such deep, vertical etching of single-crystal sapphire. A gas mixture of Cl2/BCl3/Ar was used to etch the sapphire with process variables including BCl3 flow ratio and bias power. By etching for 540 min under optimal conditions, we obtained an x-ray resonant cavity with a depth of 95 µm, width of ~30 µm, gap of ~115 µm and sidewall profile internal angle of 89.5°. The results show that the etching parameters affected the quality of the vertical sidewall, which is essential for good x-ray resonant cavities.

  2. Comparison of inductively coupled plasma mass spectrometry and colorimetric determination of total and extractable phosphorus in soils

    NASA Astrophysics Data System (ADS)

    Ivanov, Krasimir; Zaprjanova, Penka; Petkova, Milena; Stefanova, Violeta; Kmetov, Veselin; Georgieva, Deyana; Angelova, Violina

    2012-05-01

    The most widely used method for determination of total phosphorus in soils is perchloric acid digestion, followed by a colorimetric assay to measure the concentration of P in solution. The first part of this study compares an alternative digestion method, using aqua regia (ISO 11466 and EPA Method 3052), with perchloric acid digestion procedure, and also compares inductively coupled plasma mass spectroscopy (ICP-MS) with colorimetry for the measurement of P on the basis of five internationally certified standard soils and 20 real-life soils with widely different extractability of phosphorus. The phosphorus concentration was determined by means of the reduced phosphomolybdenum blue and ICP-MS. The relationship between methods has been examined statistically. Good agreement of the results from colorimetry and ICP-MS was established for all certified soils. The microwave-assisted digestion with aqua regia was comparable, both in precision and accuracy, with the hot plate aqua regia method. The phosphorus concentration found with the HF + HClO4 digestion method was in good agreement with the certified mean values, while the superiority in extracting phosphorus, when compared to other methods, was obvious. Soil testing for plant-available phosphorus in Bulgaria and many European countries is most commonly conducted using acid Ca-lactate extraction (Egner-Riehm test) and alkaline sodium bicarbonate extraction (BDS ISO 11263:2002), based on Olsen test, followed by a colorimetric assay to measure the concentration of P in solution. The second part of this study reports the differences between Egner-Riehm test and BDS ISO 11263:2002 measured colorimetrically and by ICP-MS. Fifty soils were selected from South Bulgaria to represent a wide range of soil properties. It was established that ICP-MS consistently yielded significantly higher P concentrations than the colorimetric method in both extraction tests, and the relative differences were greatest in soils with lower P

  3. The induction of water to the inlet air as a means of internal cooling in aircraft-engine cylinders

    NASA Technical Reports Server (NTRS)

    Rothrock, Addison M; Krsek, Alois, Jr; Jones, Anthony W

    1943-01-01

    Report presents the results of investigations conducted on a full-scale air-cooled aircraft-engine cylinder of 202-cubic inch displacement to determine the effects of internal cooling by water induction on the maximum permissible power and output of an internal-combustion engine. For a range of fuel-air and water-fuel ratios, the engine inlet pressure was increased until knock was detected aurally, the power was then decreased 7 percent holding the ratios constant. The data indicated that water was a very effective internal coolant, permitting large increases in engine power as limited by either knock or by cylinder temperatures.

  4. MICROSCALE FLOW INJECTION AND MICROBORE HIGH-PERFORMANCE LIQUID CHROMATORGRAPHY COUPLED WITH INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY VIA A HIGH-EFFICIENCY NEBULIZER

    EPA Science Inventory

    A high-effeciency nebulizer has been used for coupling microscale flow injection and microbore high-performance liquid chromatography with inductively coupled plasma mass spectrometry (ICPMS). The microscale flow injection system was configured to minimize band broadening between...

  5. A Plasma Rocket Demonstration on the International Space Station

    NASA Astrophysics Data System (ADS)

    Petro, A.

    2002-01-01

    in the development of a magneto-plasma rocket for several years. This type of rocket could be used in the future to propel interplanetary spacecraft. One feature of this concept is the ability to vary its specific impulse so that it can be operated in a mode that maximizes propellant efficiency or a mode that maximizes thrust. For this reason the system is called the Variable Specific Impulse Magneto-plasma Rocket or VASIMR. This ability to vary specific impulse and thrust will allow for optimum low thrust interplanetary trajectories and results in shorter trip times than is possible with fixed specific impulse systems while preserving adequate payload margins. demonstrations are envisioned. A ground-based experiment of a low-power VASIMR prototype rocket is currently underway at the Advanced Space Propulsion Laboratory. The next step is a proposal to build and fly a 25-kilowatt VASIMR rocket as an external payload on the International Space Station. This experiment will provide an opportunity to demonstrate the performance of the rocket in space and measure the induced environment. The experiment will also utilize the space station for its intended purpose as a laboratory with vacuum conditions that cannot be matched by any laboratory on Earth. propulsion on the space station. An electric propulsion system like VASIMR, if provided with sufficient electrical power, could provide continuous drag force compensation for the space station. Drag compensation would eliminate the need for reboosting the station, an operation that will consume about 60 metric tons of propellant in a ten-year period. In contrast, an electric propulsion system would require very little propellant. In fact, a system like VASIMR can use waste hydrogen from the station's life support system as its propellant. This waste hydrogen is otherwise dumped overboard. Continuous drag compensation would also improve the microgravity conditions on the station. So electric propulsion can reduce propellant

  6. Online tuning of impedance matching circuit for long pulse inductively coupled plasma source operation—An alternate approach

    SciTech Connect

    Sudhir, Dass; Bandyopadhyay, M. Chakraborty, A.; Kraus, W.; Gahlaut, A.; Bansal, G.

    2014-01-15

    Impedance matching circuit between radio frequency (RF) generator and the plasma load, placed between them, determines the RF power transfer from RF generator to the plasma load. The impedance of plasma load depends on the plasma parameters through skin depth and plasma conductivity or resistivity. Therefore, for long pulse operation of inductively coupled plasmas, particularly for high power (∼100 kW or more) where plasma load condition may vary due to different reasons (e.g., pressure, power, and thermal), online tuning of impedance matching circuit is necessary through feedback. In fusion grade ion source operation, such online methodology through feedback is not present but offline remote tuning by adjusting the matching circuit capacitors and tuning the driving frequency of the RF generator between the ion source operation pulses is envisaged. The present model is an approach for remote impedance tuning methodology for long pulse operation and corresponding online impedance matching algorithm based on RF coil antenna current measurement or coil antenna calorimetric measurement may be useful in this regard.

  7. Investigations into the origins of polyatomic ions in inductively coupled plasma-mass spectrometry

    SciTech Connect

    McIntyre, Sally M.

    2010-01-01

    An inductively coupled plasma-mass spectrometer (ICP-MS) is an elemental analytical instrument capable of determining nearly all elements in the periodic table at limits of detection in the parts per quadrillion and with a linear analytical range over 8-10 orders of magnitude. Three concentric quartz tubes make up the plasma torch. Argon gas is spiraled through the outer tube and generates the plasma powered by a looped load coil operating at 27.1 or 40.6 MHz. The argon flow of the middle channel is used to keep the plasma above the innermost tube through which solid or aqueous sample is carried in a third argon stream. A sample is progressively desolvated, atomized and ionized. The torch is operated at atmospheric pressure. To reach the reduced pressures of mass spectrometers, ions are extracted through a series of two, approximately one millimeter wide, circular apertures set in water cooled metal cones. The space between the cones is evacuated to approximately one torr. The space behind the second cone is pumped down to, or near to, the pressure needed for the mass spectrometer (MS). The first cone, called the sampler, is placed directly in the plasma plume and its position is adjusted to the point where atomic ions are most abundant. The hot plasma gas expands through the sampler orifice and in this expansion is placed the second cone, called the skimmer. After the skimmer traditional MS designs are employed, i.e. quadrupoles, magnetic sectors, time-of-flight. ICP-MS is the leading trace element analysis technique. One of its weaknesses are polyatomic ions. This dissertation has added to the fundamental understanding of some of these polyatomic ions, their origins and behavior. Although mainly continuing the work of others, certain novel approaches have been introduced here. Chapter 2 includes the first reported efforts to include high temperature corrections to the partition functions of the polyatomic ions in ICP-MS. This and other objections to preceeding

  8. Documenting utility of paddlefish otoliths for quantification of metals using inductively coupled plasma mass spectrometry

    USGS Publications Warehouse

    Long, James M.; Schaffler, James J.

    2013-01-01

    RATIONALE The otoliths of the inner ear of fishes record the environment of their surrounding water throughout their life. For paddlefish (Polyodon spathula), otoliths have not been routinely used by scientists since their detriments were outlined in the early 1940s. We sought to determine if paddlefish otoliths were useful for resolving elemental information contained within. METHODS Adult paddlefish were collected from two wild, self-sustaining populations in Oklahoma reservoirs in the Arkansas River basin. Juveniles were obtained from a hatchery in the Red River basin of Oklahoma. Otoliths were removed and laser ablation, inductively coupled plasma mass spectrometry (ICP-MS) was used to quantify eight elements (Li, Mg, Mn, Rb, Sr, Y, Ba, and Pb) along the core and edge portions, which were analyzed for differences between otolith regions and among paddlefish sources. RESULTS Differences were found among samples for six of the eight elements examined. Otoliths from Red River basin paddlefish born in a hatchery had significantly lower amounts of Mg and Mn, but higher levels of Rb than otoliths from wild paddlefish in the Arkansas River basin. Concentrations of Y, Sr, and Ba were reduced on the edges of adult paddlefish from both reservoirs compared with the cores. CONCLUSIONS This research shows the utility of using an ICP-MS analysis of paddlefish otoliths. Future research that seeks to determine sources of paddlefish production, such as which reservoir tributaries are most important for reproduction or what proportion of the population is composed of wild versus hatchery-produced individuals, appears promising. Published in 2013. This article is a U.S. Government work and is in the public domain in the USA.

  9. Determination of elemental impurities in poly(vinyl chloride) by inductively coupled plasma optical emission spectrometry.

    PubMed

    Pereira, Leticia S F; Pedrotti, Matheus F; Miceli, Tatiane M; Pereira, Juliana S F; Flores, Erico M M

    2016-05-15

    In this work, a method for poly(vinyl chloride) (PVC) analysis by inductively coupled plasma optical emission spectrometry (ICP-OES) was developed. Samples were digested by microwave-induced combustion (MIC) and thirteen elements (Ba, Cd, Co, Cu, Fe, Mg, Mn, Mo, Ni, Pb, Sr, V and Zn) were determined by ICP-OES. Operational conditions of MIC were investigated allowing quantitative determination of all the analytes and suitable results were achieved using a 3 mol L(-1) HNO3 solution. Microwave-assisted wet digestion (MAWD) using closed quartz vessels and a single reaction chamber microwave digestion system (MAWD-SRC), were also evaluated for PVC digestion for results comparison. All the evaluated sample preparation methods were considered suitable for PVC digestion but MIC was preferable due to the possibility of using diluted HNO3 instead of concentrated reagents and due to the better digestion efficiency. The residual carbon content (RCC) in digests obtained by MIC was significantly lower in comparison with the values obtained after MAWD and by MAWD-SRC. Accuracy for the proposed method was better than 94% for all analytes by comparison of results with those obtained by neutron activation analysis (NAA). Using MIC, it was possible to digest a relatively high sample mass (500 mg) and up to 8 samples in less time (25 min) in comparison with MAWD and MAWD-SRC (about 60 min for both methods). The efficiency of digestion by MIC was higher 99% and lower limits of detection (as low as 0.1 µg g(-1)) were obtained avoiding the use of concentrated acids that is of great concern according to the current green chemistry recommendations. PMID:26992533

  10. Determination of 28 selected elements in textiles by axially viewed inductively coupled plasma optical emission spectrometry.

    PubMed

    Rezić, Iva; Zeiner, Michaela; Steffan, Ilse

    2011-01-15

    A simple, robust and reliable analytical procedure for the determination of 28 selected elements, namely Al, As, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, K, Hg, Mg, Mn, Mo, Na, Ni, Pb, Sc, Si, Se, Sn, Sm, Sr, Tl, V, and Zn in textile materials by inductively coupled plasma optical emission spectrometry (ICP-OES) after microwave digestion of samples was optimized and validated in this work. The total amount of elements present in textile samples was determined after microwave digestion of materials in 7 mol/L nitric acid within the optimal working program: 5 min at 150°C (power 250 W), 15 min 180°C (300 W) and 20 min at the maximum temperature of 200°C (350 W). For the quality control reasons, which were ascertained by analysis of the certified cotton trace elements reference material IAEA-V9, the ICP-OES method was optimized through several parameters: by comparing Meinhard and Gemcone Low Flow nebulizers efficiency, ranging nebulizer gas flows from 0.6 to 1.0 L/min, ranging sample flows from 0.8 to 1.2 mL/min, testing RF power from 1200 to 1400 W, detecting data acquisition time (read time) from 0 to 527 s, ranging washing (delay) time from 0 to 408 s, as well as by checking the occurring interferences for the optimal line selection. Validation included determination of linearity, selectivity, accuracy, reproducibility, precision and limits of detection calculated for all 28 selected elements of interest. The developed analytical procedure was successfully applied on textile fibers (cotton, flax and hemp) as well as on standard knitted textile sample materials (cotton and wool). PMID:21147330

  11. Recent developments in inductively coupled plasma source magnetic sector multiple collector mass spectrometry

    SciTech Connect

    Halliday, A.N.; Lee, Der-Chuen; Christensen, J.C.; Jones, C.E.; Hall, C.M.; Yi, Wen; Teagle, D.; Walder, A.J.; Freedman, P.A.

    1994-11-01

    This paper describes advances in isotopic measurements that have been made with an inductively coupled plasma source magnetic sector multiple collector mass spectrometer and presents results of new experiments aimed at further evaluating the instrument`s capability. It is shown using standard solutions that trace element ratios such as Rb/Sr can be measured precisely without isotope dilution by comparison with reference solutions of known composition. Similarly, using a new wide flight tube, Pb isotopic compositions and U/Pb ratios can be accurately measured simultaneously without isotope dilution. The effects of deliberately inducing changes in the running conditions (RF power) are shown to be significant for measuring trace element ratios but not for mass bias and interference corrected isotopic compositions. Finally, it is demonstrated that precise and accurate isotopic compositions of elements as refractory as W can be determined relatively easily by solution nebulization and even by direct laser ablation of complex silicates. Isobaric interferences in such experiments are negligible. These experiments serve to highlight the remarkable potential that this new field offers for hitherto difficult isotopic measurements in nuclear, earth, environmental and medical sciences. Isotopic measurements can be made that are reproducible at high precision through a range of running conditions, even in the presence of isobaric interferences. The ability to correct for mass discrimination accurately using a second element of similar mass, the very high sensitivity for elements that are otherwise difficult to ionize, the demonstrated capability for laser ablation work and the ability to measure through a wide mass range simultaneously give this instrument major advantages over other more traditional techniques of isotopic measurement.

  12. Slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry for steelmaking flue dust analysis

    NASA Astrophysics Data System (ADS)

    Coedo, A. G.; Dorado, T.; Padilla, I.; Maibusch, R.; Kuss, H.-M.

    2000-02-01

    A commercial atomic absorption graphite furnace (AAGF), with a self-made adapter and valve system, was used as a slurry sampling cell for electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS). The system was applied to the determination of As, Sn, Sb, Se, Te, Bi, Cd, V, Ti and Mo in steelmaking flue dusts. Experimental conditions with respect to ETV and ICP-MS operating parameters were optimized. Compared to aqueous solutions, slurry samples were found to present better analyte transport. Microgram amounts of Rh were used to reduce the difference in analyte response in sensitivity for aqueous solutions of the tested analytes. No such increasing effect was observed for slurry samples and aqueous standards. An added quantity of Rh acting as modifier/carrier resulted in an increase for the same analytes in matrix-slurry solutions, even the addition of an extra Rh quantity has resulted in a decrease in the signals. The effect of Triton X-100 (used as a dispersant agent) on analyte intensity and precision was also studied. External calibration from aqueous standards spiked with 100 μg ml -1 Rh was performed to quantified 0.010 g/100 ml slurry samples. Results are presented for a certified reference electrical arc furnace flue dust (EAF): CRM-876-1 (Bureau of Analysis Samples Ltd., Cleveland, UK), a reference sample of coke ashes X-3705 (from AG der Dillinger Hüttenwerke, Germany), and a representative sample of EAF flue dust from a Spanish steelmaking company (CENIM-1). For the two reference materials an acceptable agreement with certificate values was achieved, and the results for the CENIM sample matched with those obtained from conventional nebulization solution.

  13. Photochemical vapor generation of lead for inductively coupled plasma mass spectrometric detection

    NASA Astrophysics Data System (ADS)

    Duan, Hualing; Zhang, Ningning; Gong, Zhenbin; Li, Weifeng; Hang, Wei

    2016-06-01

    Photochemical vapor generation (PCVG) of lead was successfully achieved with a simplified and convenient system, in which only low molecular weight organic acid and a high-efficiency photochemical reactor were needed. The reactor was used to generate lead volatile species when a solution of lead containing a small amount of low molecular weight organic acid was pumped through. Several factors, including the concentration of acetic acid, the concentration of hydrochloride acid, and the irradiation time of UV light were optimized. Under the optimal conditions, including the addition of 0.90% (v/v) acetic acid and 0.03% (v/v) hydrochloride acid, and irradiation time of 28 s, intense and repeatable signal of lead volatile species was successfully obtained and identified with inductively coupled plasma mass spectrometry (ICPMS). In addition, the effects from inorganic anions and transition metal ions, including Cl-, NO3-, SO42 -, Cu2 +, Fe3 +, Co2 + and Ni2 +, were investigated, which suggests that their suppression to the PCVG of lead was in the order of Cl- < SO42 - < NO3- for anions and Ni2 +, Co2 + < Fe3 + < Cu2 + for transition metal ions. Under optimized conditions, relative standard derivation (RSD) of 4.4% was achieved from replicate measurements (n = 5) of a standard solution of 0.1 μg L- 1 lead. And, the limit of quantitation (LOQ, 10σ) of 0.012 μg L- 1 lead was obtained using this method and the method blank could be easily controlled down to 0.023 μg L- 1. To validate applicability of this method, it was also employed for the determination of lead in tap water, rain water and lake water.

  14. Multi-element analysis of compost by laser ablation-inductively coupled plasma mass spectrometry.

    PubMed

    Jiménez, María S; Gómez, María T; Castillo, Juan R

    2007-05-15

    Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been applied to multi-element determination in compost samples. Since compost is a heterogeneous mixture of organic and inorganic materials, the influence of sample heterogeneity on the accuracy and precision of analysis was investigated. Several parameters related to the following were studied: laser (energy, laser-beam diameter, preablation. rastering speed, carrier-gas flow rate), sample preparation (use of compacted pellets, grinding time, particle size, sample amount, length of hydraulic press treatment, position of line scan), and the ICP-MS system (quantitative versus semiquantitative analysis, matrix-matched standards and liquid standards calibration). The main causes of imprecision in sample preparation were determined to be particle size and grinding time. The effect of sample heterogeneity on precision was also evaluated by using different test samples (pellets). For Ni, Zn and Pb, the greatest contribution to the total relative standard deviation (R.S.D.) was related to analyte determination. For Mn and Cu, sample heterogeneity and analyte determination contributed equally to the total R.S.D., whereas for Cr, Co, Cd and Hg sample heterogeneity accounted for most of the total R.S.D. A comparison of semiquantitative and quantitative analysis modes showed that better precision and very good agreement with certified reference material was obtained with the latter, but semiquantitative analysis could be a practical alternative. Although accuracy of results was improved with matrix-matched standards calibration the use of standard addition calibration with aqueous standards could be another possibility. PMID:19071737

  15. Laser ablation inductively coupled plasma optical emission spectrometry for analysis of pellets of plant materials

    NASA Astrophysics Data System (ADS)

    Gomes, Marcos S.; Schenk, Emily R.; Santos, Dário; Krug, Francisco José; Almirall, José R.

    An evaluation of laser ablation inductively coupled plasma optical emission spectroscopy (LAICP OES) for the direct analysis of pelleted plant material is reported. Ground leaves of orange citrus, soy and sugarcane were comminuted using a high-speed ball mill, pressed into pellets and sampled directly with laser ablation and analyzed by ICP OES. The limits of detection (LODs) for the method ranged from as low as 0.1 mg kg- 1 for Zn to as high as 94 mg kg- 1 for K but were generally below 6 mg kg- 1 for most of the elements of interest. A certified reference material consisting of a similar matrix (NIST SRM 1547 peach leaves) was used to check the accuracy of the calibration and the reported method resulted in an average bias of ~ 5% for all the elements of interest. The precision for the reported method ranged from as low as 4% relative standard deviation (RSD) for Mn to as high as 17% RSD for Zn but averaged ~ 6.5% RSD for all the elements (n = 10). The proposed method was tested for the determination of Ca, Mg, P, K, Fe, Mn, Zn and B, and the results were in good agreement with those obtained for the corresponding acid digests by ICP-OES, no differences being observed by applying a paired t-test at the 95% confidence level. The reported direct solid sampling method provides a fast alternative to acid digestion that results in similar and appropriate analytical figures of merit with regard to sensitivity, accuracy and precision for plant material analysis.

  16. Acquisition of a High-resolution Inductively Coupled Plasma Mass Spectrometer for Cosmochemical and Geochemical Research

    NASA Technical Reports Server (NTRS)

    Lauretta, D. S.

    2004-01-01

    The primary goal of our research in this program is to develop new techniques for the analysis of volatile trace elements in very small samples using inductively coupled plasma mass spectrometry (ICP-MS) in preparation for samples returned by the Stardust mission. The instrument that will serve as the basis of our experiments is the ELEMENT2 high-resolution ICP-MS. We have spent the past year designing the laboratory to house this instrument as well as space to store and prepare samples returned by the Stardust mission. Unfortunately, the location that we had initially selected for the instrument turned out to be insufficient for our needs. This was determined almost eight months into the first year of our funding cycle, after extensive work including the production of engineering drawings. However, during this time the Lunar and Planetary Laboratory was selected to lead Phoenix, the first Mars Scout mission. As a result of this award LPL purchased a new, 50,000 square foot building. We have acquired 1400 square feet of laboratory space in this new facility. Four-hundred square feet will be used for a class-100 clean room. This area is designated for storage and preparation of extraterrestrial materials. The additional 1000 square feet will house the ELEMENT2 ICP-MS and peripheral devices. This is an enormous amount of space for this instrument, but it provides plenty of room for expansion in the future. The ICP-MS and the clean room facilities have been purchased. The instrument has been delivered. The startup time for this instrument is relatively short and we expect to be collecting our first data by mid-summer.

  17. Gunshot residue testing in suicides: Part II: Analysis by inductive coupled plasma-atomic emission spectrometry.

    PubMed

    Molina, D Kimberley; Castorena, Joe L; Martinez, Michael; Garcia, James; DiMaio, Vincent J M

    2007-09-01

    Several different methods can be employed to test for gunshot residue (GSR) on a decedent's hands, including scanning electron microscopy with energy dispersive x-ray (SEM/EDX) and inductive coupled plasma-atomic emission spectrometry (ICP-AES). In part I of this 2-part series, GSR results performed by SEM/EDX in undisputed cases of suicidal handgun wounds were studied. In part II, the same population was studied, deceased persons with undisputed suicidal handgun wounds, but GSR testing was performed using ICP-AES. A total of 102 cases were studied and analyzed for caliber of weapon, proximity of wound, and the results of the GSR testing. This study found that 50% of cases where the deceased was known to have fired a handgun immediately prior to death had positive GSR results by ICP/AES, which did not differ from the results of GSR testing by SEM/EDX. Since only 50% of cases where the person is known to have fired a weapon were positive for GSR by either method, this test should not be relied upon to determine whether someone has discharged a firearm and is not useful as a determining factor of whether or not a wound is self-inflicted or non-self-inflicted. While a positive GSR result may be of use, a negative result is not helpful in the medical examiner setting as a negative result indicates that either a person fired a weapon prior to death or a person did not fire a weapon prior to death. PMID:17721164

  18. Determination of Pu in urine at ultratrace level by sector field inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Zoriy, M. V.; Pickhardt, C.; Ostapczuk, P.; Hille, R.; Becker, J. S.

    2004-04-01

    A new analytical procedure has been developed for the determination of Pu in urine at the low ag ml-1 concentration level by double-focusing sector field inductively coupled plasma mass spectrometry (ICP-SFMS). One liter of urine doped with 4 pg 242Pu was analyzed after co-precipitation with Ca3(PO4)2 followed by extraction chromatography on TEVA resin in order to enrich the Pu and remove uranium and matrix elements. Figures of merit of ICP-SFMS for the determination of Pu were studied using two nebulizers, PFA-100 and direct injection high-efficiency nebulizer (DIHEN), for solution introduction with uptake rates of 0.58 and 0.06 ml min-1, respectively. The sensitivity for Pu in ICP-SFMS was determined to be 2000 and 1380 MHz ppm-1 for the PFA-100 and DIHEN nebulizers, respectively. Due to the low solution uptake rate of DIHEN the absolute sensitivity was about seven times better and yielded 1380 counts fg-1 in comparison to 207 counts fg-1 measured with the PFA-100 nebulizer. Recovery using 242Pu tracer was about 70%. The limits of detection for 239Pu in 1 l of urine, based on an enrichment factor of 100 for PFA-100 nebulizer and 1000 for DIHEN, were 9×10-18 and 1.02×10-18 g ml-1, respectively. Measurements of 240Pu/239Pu isotopic ratio in synthetically prepared urine standard solution yielded a precision of 1.8 and 1.9% and accuracy of 1.5 and 1.8% for the PFA-100 and DIHEN nebulizers, respectively.

  19. Multi-Collector Inductively Coupled Plasma Mass Spectrometer – Operational Performance Report

    SciTech Connect

    Matthew Watrous; Anthony Appelhans; Robert Hague; John Olson; Tracy Houghton

    2013-06-01

    The INL made an assessment of the commercially available inductively coupled plasma mass spectrometers (ICPMS) for actinide analysis; emphasizing low detection limits for plutonium. INL scientists subsequently determined if plutonium was present on a swipe, at a 10 million atom decision level. This report describes the evaluation of ICPMS instruments and the operational testing of a new process for the dissolution, separation and analysis via ICPMS of swipes for plutonium and uranium. The swipe dissolution, plutonium and uranium isolation, separation and purification are wet chemistry methods following established procedures. The ICPMS is a commercially available multi-collector magnetic sector mass spectrometer that utilizes five ion counting detectors operating simultaneously. The instrument includes a sample introduction system allowing for sample volumes of < 1 mL to be reproducibly injected into the instrument with minimal waste of the sample solution, while maximizing the useable signal. The performance of the instrument was measured using SRM 996 (244Pu spike) at concentrations of 12 parts per quadrillion (ppq, fg/mL) and with SRM 4350B Columbia River Sediment samples spiked onto swipes at the 10 million atom level. The measured limit of detection (LOD, defined as 3s) for 239Pu is 310,000 atoms based upon the instrument blank data. The limit of quantification (LOQ defined as 10 s) for 239Pu is 105,000 atoms. The measured limit of detection for 239Pu from the SRM 4350B spiked onto a swipe was 2.7 million atoms with the limit of quantification being 9.0 million atoms.

  20. Calibration of laser ablation inductively coupled plasma mass spectrometry for quantitative measurements of lead in bone.

    PubMed

    Bellis, David J; Hetter, Katherine M; Jones, Joseph; Amarasiriwardena, Dula; Parsons, Patrick J

    2006-01-01

    Lead accumulates in bone over many years or decades. Accordingly, the study of lead in bone is important in determining the fate of ingested lead, the potential for remobilization, and for the application of bone lead measurements as a biomarker of lead exposure. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used to measure the spatial distribution of lead in bone on the micrometer scale. In general, LA-ICP-MS studies are somewhat limited by the lack of matrix-matched standards and/or reference materials for calibration and validation purposes. Here we describe the application of pressed pellets prepared from New York State Department of Health candidate Reference Materials for Lead in Bone (levels 1 through 4), to provide a linear calibration for (208)Pb/(43)Ca in the concentration range <1 to 30 μg g(-1). The limit of detection was estimated as 0.2 μg g(-1). The measured lead values for pelletized NIST SRM 1486 Bone Meal and SRM 1400 Bone Ash were in good agreement with certified reference values. Using this approach, we quantitatively measured the spatial distribution of lead in a cross-section of goat metacarpal from a lead-dosed animal. The lead content was spatially variable in the range of 2 to 30 μg g(-1) with a complex distribution. In some sections, lead appeared to be enriched in the center of the bone relative to peripheral areas, indicating preferential accumulation in trabecular (spongy) rather than cortical bone. In addition, there were discrete areas of lead enrichment, or hot spots, of 100 to 200 μm in width. PMID:22833692