Radiant emittance of xenon positive column discharges

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:63077

Doughty, D A; Fobare, D F ^[1]

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1. General Electric Co., Schenectady, NY (United States). Corporate Research and Development

An embodiment of a mercury-free fluorescent lamp combines a low pressure rare gas discharges with a phosphor having a quantum efficiency grater than one. The choice of the rare gas depends on a number of factors, one of which is the resonance transition energy. Less demand is placed the quantum efficiency of the phosphor for a lower energy resonance photon. Xenon has the lowest energy resonance transition of the stable rare gases at 8.5 eV (147 nm) and thus is a good candidate to study. The usefulness of a xenon-based discharge depends on the radiant emittance of the discharge at the resonance wavelength of 147 nm. The radiant emittance from a low pressure xenon positive column discharge is measured using two independent techniques. The first relies on the measurement of the resonance level density using absorption techniques. The effective decay rate of the resonance level is calculated using radiation trapping theory. The product of this density and trapped decay rate yields the radiant emittance. The second technique measures the 147 nm radiance normal to the positive column axis using a NIST-calibrated cesium-telluride photodiode. These plasmas tend not to be diffuse radiators so that the angular distribution of the 147 nm radiation cannot be assumed to be cosine. The angular distribution of the resonance radiation is determined from a Monte Carlo simulation of the transport of resonance radiation in a cylindrical geometry. The photodiode measurement places the angular distribution of the radiance on an absolute scale, which can then be integrated to yield the radiant emittance.

• OSTI ID: 63077
• Report Number(s): CONF-940604--; ISBN 0-7803-2006-9
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
BRIGHTNESS
DESIGN
ELECTRIC DISCHARGES
FLUORESCENT LAMPS
MEASURING METHODS
RADIATION TRANSPORT
XENON