摘要:

A new synchronous detector has been built. Based on a resistive network and instrument thermocouples, it has a flat frequency response from 0 to radio frequencies. Bandwidth is reduced by thermal capacity in the thermocouples. Analysis provides design criteria of general utility and these criteria are applied to a prototype.

ISSN:0034-6748    

DOI:10.1063/1.1720457

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

The positive ion current extracted from an electrodeless discharge is studied as a function of the discharge parameters of oscillator input power and frequency, gas pressure, magnetic field, extraction voltage, and extraction electrode geometry. A greatly enhanced ion current is obtained by operating the discharge at a pressure of several microns of mercury and applying a static magnetic field either parallel or perpendicular to the magnetic component of the high frequency electromagnetic field. Mean beam energies up to 200 eV above the extraction voltage and beam energy spreads of 50 eV are observed and studied as functions of the discharge parameters.

ISSN:0034-6748    

DOI:10.1063/1.1720458

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

This paper describes a free space method for measuring the permittivity at X band and higher frequencies over a wide temperature range. Measurements are limited to values of &egr;′>6 and 10−3<tan&dgr;<0.2. &egr;′ can be determined to 1 or 2% over a significant range; however, for tan&dgr; the range and accuracy are limited. X band measurements are presented for ZrO2at room temperature and Al2O3at room temperature, 1100°C, and 1450°C. Elevated temperature measurements can be performed without heating the microwave components. This method is suitable for use in the millimeter wavelength region. Curves for use in evaluating &egr;′ and tan&dgr; have been previously recorded by the author [``Values for Scattering by Dielectric Spheres in the Region of the First Resonance,'' NRL Report 6365 (30 December 1965)].

ISSN:0034-6748    

DOI:10.1063/1.1720459

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

A sensitive image orthicon slit spectrograph has been developed for the investigation of aurora and night air glow, particularly with respect to their time changing characteristics. The equipment design meets the following specifications: sensitivity, 20 photoelectrons produce a detectable signal; dynamic range, 200:1; resolution, 5–30 Å; spectrum coverage, 3800 to 8200 Å; and typical exposure required on a just visible aurora, 1 sec, on night air glow, 10 sec.

ISSN:0034-6748    

DOI:10.1063/1.1720460

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

A standard has been developed for calibrating uranium hexafluoride pressure gauges in the micron region. The device employs the equilibrium dissociation pressure of uranium hexafluoride furnished by the sodium fluoride complex salt at easily controlled temperatures above ambient. The pressure signal obtained is in good agreement with reported dissociation pressure measured by the transpiration method. The principles are applicable to noncorrosive gas‐solid systems; for example, some oxides, carbonates, and hydrates dissociate to reversibly give a definite oxygen, carbon dioxide, or water vapor pressure at a given temperature.

ISSN:0034-6748    

DOI:10.1063/1.1720461

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

A technique is described which permits extraction of ions from a flame burning at atmospheric pressure, and identification of these ions by a time‐of‐flight mass spectrometer. The sampling system (consisting of a differentially pumped inlet system for rapidly reducing the pressure, a series of ion lenses for collimating the incoming beam, and a grid system for decelerating and bunching the ions as they enter the mass spectrometer) is described in detail, and performace data for the system are presented.

ISSN:0034-6748    

DOI:10.1063/1.1720462

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

A tantalum oven that produces quiescent isothermal cesium plasmas at precisely known temperatures and pressures is described. The apparatus consists of a closed, cesium vapor filled tube heated by radiation within a resistance heated vacuum furnace. Plasma temperatures up to 2300°K and cesium vapor pressures up to 10 Torr are obtainable. Temperatures are measured by calibrated unsheathed W/W‐26%Re thermocouples. Cesium vapor pressures are known through careful control of the cesium condensation conditions. Designed especially for spectroscopic studies, the oven features two sapphire windows mounted on a line‐of‐sight axis through the plasma. Details of construction and operation are described. Performance data showing temperature profiles to 1% over a 10 cm length are given.

ISSN:0034-6748    

DOI:10.1063/1.1720463

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

An automatically controlled absorption cell thermostat with a useful range of from −150 to +60°C is described and has been successfully used with a commercial spectrophotometer (Cary 14). This apparatus accepts ordinary cylindrical absorption cells to 5 cm in length.

ISSN:0034-6748    

DOI:10.1063/1.1720464

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

A theoretical and experimental study is made of a device that measures the conductivity and velocity of plasma streams. The instrument consists of a primary coil and several secondary coils. Alternating current through the primary coil produces an oscillating magnetic field in the shape of a dipole. Positions of the secondary coils relative to the primary are such that they respond to distortions of the applied magnetic field of the primary that are brought about by the presence and motion of an electrically conducting fluid. These signals on the secondaries vary linearly with the conductivity and with the product of conductivity times velocity. Various possible coil arrangements and the results of tests conducted with a simple three coil configuration in an electric arc jet are presented. Details of the probe tested, its calibration, and its theoretical basis are described. Results obtained with the three coil system are in good agreement with theory.

ISSN:0034-6748    

DOI:10.1063/1.1720465

出版商:AIP    

年代:1966

数据来源: AIP

摘要:

A modified McLeod gauge, a mercury manometer, and gas sampling apparatus are combined into one instrument. A sample of gas may be taken under static condition at a known, measurable pressure from atmospheric to 5×10−4Torr with this instrument.

ISSN:0034-6748    

DOI:10.1063/1.1720466

出版商:AIP    

年代:1966

数据来源: AIP