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Results for “DISCHARGE TUBE”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

CO2 laser cold cathode study

The procedure for evaluating reliable sputter-free cold cathodes for carbon dioxide lasers is discussed. The purpose of the development is to obtain cold cathodes with service life in excess of 10,000 hours. Discharge tubes are used to eliminate the materials which would be unsatisfactory for use as a cold cathode. A description of the facility for producing the discharge tubes is described. The gas monitoring technique for determining discharge tube performance is examined. Discharge characteristics of tubes with various metals for cathode material are presented in chart form.

Hochuli, U.↗
NASA NTRS1994

Double-ended metal halide arc discharge lamp with electrically isolated containment shroud

A double-ended arc discharge lamp includes a sealed, light-transmissive outer jacket, a light-transmissive shroud mounted within the outer jacket and directly supported by the outer jacket, and an arc discharge tube mounted within the shroud. The arc tube is typically a metal halide arc discharge tube. In a preferred embodiment, the shroud includes an outwardly flared portion at each end. The outwardly flared portions space the shroud from the outer jacket and support the shroud within the outer jacket. The outwardly flared portions of the shroud can be affixed to the outer jacket by fusing. The outer jacket can be provided with inwardly extending dimples for locating the shroud with respect to the outer jacket. In another embodiment, the outer jacket includes reduced diameter portions near each end which are attached to the shroud.

Muzeroll, Martin M.↗
NASA NTRS1994

Double-ended metal halide arc discharge lamp with electrically isolated containment shroud

A double-ended arc discharge lamp includes a sealed, light-transmissive outer jacket, a light-transmissive shroud mounted within the outer jacket and directly supported by the outer jacket, and an arc discharge tube mounted within the shroud. The arc tube is typically a metal halide arc discharge tube. In a preferred embodiment, the shroud includes an outwardly flared portion at each end. The outwardly flared portions space the shroud from the outer jacket and support the shroud within the outer jacket. The outwardly flared portions of the shroud can be affixed to the outer jacket by fusing. The outer jacket can be provided with inwardly extending dimples for locating the shroud with respect to the outer jacket. In another embodiment, the outer jacket includes reduced diameter portions near each end which are attached to the shroud.

Muzeroll, Martin M.↗
NASA NTRS1973

A composite model for a class of electric-discharge shock tubes

A gasdynamic model is presented and analyzed for a class of shock tubes that utilize both Joule heating and electromagnetic forces to produce high-speed shock waves. The model consists of several stages of acceleration in which acceleration to sonic conditions is achieved principally through heating, and further acceleration of the supersonic flow is obtained principally through use of electromagnetic forces. The utility of the model results from the fact that it predicts a quasi-steady flow process, mathematical analysis is straightforward, and it is even possible to remove one or more component stages and still have the model related to a possible shock-tube flow. Initial experiments have been performed where the electrical discharge configuration and current level were such that Joule heating was the dominant form of energy addition present. These experiments indicate that the predictions of the model dealing with heat addition correspond quite closely to reality. The experimental data together with the theory show that heat addition to the flowing driver gas after diaphragm rupture (approach used in the model) is much more effective in producing high-speed shock waves than heating the gas in the driver before diaphragm rupture, as in the case of the arc-driven shock tube.

Elkins, R. T.↗
NASA NTRS1974

Minimization of the prime power consumption of a coupling-modulated gas laser transmitter

The present article addresses itself to the prime power requirements of a coupling-modulated gas laser transmitter. The latter consists of a gas discharge tube and electrooptic modulator inside a laser resonator. In performing the calculations, the laser discharge length and the modulator voltage are simultaneously varied so that the transmitted power remains constant. In this way, tradeoffs can be made between the prime power supplied individually to the discharge tube and to the modulator driver to obtain a transmitter configuration that minimizes the total prime power consumption. An analytical expression is derived that describes the effects of information bandwidth and transmitter output power on the prime power requirements. Specific numerical results are obtained for a CO2 laser transmitter based on presently available experimental data.

Degnan, J. J.↗
NASA NTRS1982

Standing waves along a microwave generated surface wave plasma

Two surface wave plasma columns, generated by microwave power in argon at gas pressures of 0.05 torr to 330 torr, interact in the same discharge tube to form standing surface waves. Radial electric field and azimuthal magnetic field outside the discharge tube are measured to be 90 deg out of phase with respect to axial position and to decay exponentially with radial distance from the tube axis. Maximum light emission occurs at the position of maximum azimuthal magnetic field and minimum radial electric field. Electron temperature and density are measured at low pressures with double probes inserted into the plasma at a null of radial electric field. Measured electron densities compare well with those predicted by Gould-Trivelpiece surface wave theory.

Rogers, J.↗
NASA NTRS1973

On the minimization of the prime power consumption of a coupling-modulated gas laser transmitter

The prime power requirements of a coupling-modulated gas laser transmitter are presented. The latter consists of a gas discharge tube and electro-optic modulator inside a laser resonator. In performing the calculations, the laser discharge length and the modulator voltage are simultaneously varied so that the transmitted power remains constant. In this way, tradeoffs can be made between the prime power supplied individually to the discharge tube and to the modulator driver to obtain a transmitter configuration which minimizes the total prime power consumption. An analytical expression is derived which describes the effects of information bandwidth and transmitter output power on the prime power requirements. Specific numerical results are obtained for a CO2 laser transmitter based on presently available experimental data.

Degnan, J. J.↗
NASA NTRS1973

Double-discharge copper vapor laser with copper chloride as a lasant

A copper vapor laser utilizing copper chloride as a lasant in a heated discharge tube has been studied. The lasing action was observed only when two successive discharge current pulses at suitable time intervals were applied. The first pulse is considered to be a dissociation pulse to produce copper and chlorine atoms; the second to be a pumping pulse to produce population inversion. The maximum energy density measured to date was 17 microjoule/cu cm.

Chen, C. J.↗
NASA NTRS1979

High current hollow cathode tube as a source of metastable atoms

A source for the continuous production of neutral metastable atoms is described. A hollow cathode discharge tube was used to produce densities of 3.5 times 10 to the 13th per cu cm and column densities of 1.6 times 10 to the 15th per sq cm in the 4s(2)2D metastable term of neutral copper. The accuracy of these density determinations (+ or - 30 to + or - 66%) is limited by the oscillator strengths required for the analysis. The usefulness of the source was demonstrated by measurements of relative oscillator strengths of some Cu I lines in the 2200 A wavelength region. These data are compared with those obtained by other methods.

Lombardi, G. G.↗
NASA NTRS1983

Laser optogalvanic spectroscopy of molecules

In laser optogalvanic (LOG) spectroscopy, a tunable laser is used to probe the spectral characteristics of atomic or molecular species within an electrical discharge in a low pressure gas. Optogalvanic signals arise when the impedance of the discharge changes in response to the absorption of laser radiation. The technique may, therefore, be referred to as impedance spectroscopy. This change in impedance may be monitored as a change in the voltage across the discharge tube. LOG spectra are recorded by scanning the wavelength of a chopped CW dye laser while monitoring the discharge voltage with a lock-in amplifier. LOG signals are obtained if the laser wavelength matches a transition in a species present in the discharge (or flame), and if the absorption of energy in the laser beam alters the impedance of the discharge. Infrared LOG spectroscopy of molecules has been demonstrated and may prove to be the most productive application in the field of optogalvanic techniques.

Webster, C. R.↗