Radiation efficiency of Hg-Ar surface wave discharges

Abstract

The radiation efficiency of Hg-Ar low-pressure surface wave (SW) discharges has been measured in a broad range of Ar pressures (40 mTorr-12 Torr), Hg partial pressures ( approximately 1-100mTorr) and excitation frequencies (200-1000 MHz). Gas filling and tube geometry (26 mm outer diameter) were chosen to allow a comparison with the conventionally excited Hg-Ar low-pressure discharge used for general lighting purposes in the well known fluorescent lamp. The study focuses on the quantitative measurement of the two Hg UV resonance lines at 185 and 254 nm. The RF power input into the plasma column extending outside the surfatron coupling structure was determined quantitatively. This was done by measuring the power dissipated in the part of the plasma column hidden within the surfatron by a calorimetric method. The measurements of the Hg UV radiation efficiency are supplemented by radial scan experiments of a visible Hg line, and by the study of phenomena occurring at a higher power density such as saturation and standing wave formation.

Travelling-wave-sustained discharges

“…Many possibilities for the use of TWSDs for surface processing and film deposition [12,149,[194][195][196][197][198][199][200][201][202][203][204][205][206][207][208][209][210][211][212][213], gas detoxification [214][215][216][217], for sterilization [218], for light sources [219][220][221][222][223] and lasers [224][225][226], for panel displays [227], for particle sources [228][229][230][231][232][233][234][235][236][237][238][239], for elementary analysis through atomic spectroscopy …”

Microwave photochemistry V: Low‐pressure batch and continuous‐flow microwave photoreactors with quartz mercury electrodeless discharge lamps. Photohydrolysis of mono‐chloroacetic acid

“…38,39 Also, at this temperature a strong reduction in the intensity of the inert gas lines has been observed. 36 On the other hand, the rate of MCAA photohydrolysis is also determined and quantified by the quantum yield, defined as = (yield of photoproducts)/(number of photons absorbed).…”

Electrodeless lamps for lighting: a review

“…When the discharge reaches the end of the tube, the surface wave appears to be reflected so that the discharge is enhanced and made more uniform [54]. At high frequencies, evidence of this reflection appears in the form of standing waves [55]. A helical wire of a few turns wrapped round the tube can also increase uniformity of power dissipation and light output [54].…”