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  • 1
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We have constructed and tested a prototype instrument for space plasma physics research. The instrument is capable of measuring total ion velocity distribution functions as well as velocity distribution functions for individual mass-per-charge (m/q) species. The instrument consists of a deflection system, a toroidal energy-per-charge (E/q) analyzer, and a hemispherical condenser that serves either as the second stage of E/q analysis or as a gated time-of-flight velocity filter. The deflection system subtends a full 360° in azimuth and allows one to select ions for analysis in the toroidal section according to their elevation angle with respect to the axis of the instrument. The hemispherical condenser accepts a fraction of the ions transmitted by the toroidal analyzer through an electronic shutter at its entrance plane. With the shutter open, total ion distribution functions are measured. By appropriately gating the shutter and measuring the time of flight of ions introduced into the hemisphere, ion velocities are measured and m/q determined. The dimensions of the instrument have been chosen for measurements of the interplanetary solar wind at distances of 4–20 solar radii (Rsun) from the surface of the sun, consistent with the requirements of a solar probe mission. It can also be adapted to make measurements at 1 a.u. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The polarization behaviour of acid copper solutions containing polyethers, sulphopropyl sulphides and chloride ions was studied using both direct and pulsed reverse current. The effect of these additives on the rest potentials of copper foils immersed in the electrolyte was also studied. Polyethers were found to have an inhibiting effect on the deposition of copper whereas the sulphopropyl sulphides produced a stimulating (i.e. depolarizing) effect. Chloride ion concentration was found to have an influence on the adsorption characteristics of the polyether. The use of pulsed reverse current in solutions containing both polyether and sulphopropyl sulphide was found to inhibit the adsorption/diffusion of the sulphopropyl sulphide at the cathode surface. Thus at higher current densities, above 2 A dm−2, the inihibiting effect of the polyether produced a shift in the cathodic polarization potential to more negative values as compared with an equivalent current density using direct current. At lower current densities, below 2 A dm−2, the depolarization effect of the sulphopropyl sulphide was still effective. This effect of pulsed current on additive containing solutions can improve dramatically the metal distribution in low current density areas on plated items. This was illustrated by plating Hull cell panels using both pulsed and direct current.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 68 (1997), S. 1604-1608 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We report on our investigation into the development of electrostatic mirror based charged particle analyzers for space plasma physics experimentation. For this work, we tested an elliptical mirror analyzer which was designed to provide a wide, 2-dimensional field of view with high throughput and good angular resolution. Measurements with an ion beam demonstrated 2° full width at half-maximum angular resolution over a 16×16° field of view (FOV) and 4° resolution over a 40×40° FOV for an optical system with a linear dimension (entrance aperture to the particle detector) of 20 cm. The energy resolution is variable, similar in operation to a retarding-potential-analyzer or a modulated grid Faraday cup, with a geometric factor of 3.2×10−3 cm2 str ΔE/E for an energy resolution setting of 10%. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: High-density plasmas are being used in the manufacture of electronic devices and systems because they provide high throughput at low pressure and low ion energy. Low pressure is desirable for maximizing process uniformity over large substrates while low ion energy is desirable for minimizing process-induced damage. However, the optimal design for a high density plasma reactor is unclear and the technology has largely developed empirically: many alternatives for magnetic and geometric design are offered for the same processing applications. In this talk we discuss diagnostic measurements of high density plasma reactors and how they can be used in developing improved reactor designs and in providing insight into materials processing. Laser-induced fluorescence measurements of metastable ion velocity distributions are made in both Ar and Cl2 electron cyclotron resonance and helicon plasmas. The effects of magnetic field configuration, power, and pressure on the energy and angular distributions of the ions will be described along with electron density measurements made by microwave interferometry. Where appropriate, comparisons will be made with the recent theoretical results of Graves and Porteous [D. B. Graves and R. K. Porteous, American Vacuum Society National Symposium, Seattle, WA, November (1991)].
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A simple, inexpensive method for precisely calibrating high resolution, pulsed dye lasers in the 500–340-nm wavelength region has been devised. The residual portion of the laser beam exiting from an experiment is Raman shifted to longer wavelnegths in a high-pressure hydrogen cell. The Stokes shifted output is used to excite laser induced fluorescence (LIF) signals in I2 vapor, which, in turn, are used to accurately calibrate the wavelength of the Raman shifted beam. The constant Raman shift, which can be precisely calculated, is then added to give the original laser wavelength. The method is readily adapted to computerized data acquisition and gives results of comparable accuracy to those of I2 LIF calibrations in the conventional 850–500 nm region.
    Type of Medium: Electronic Resource
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