Ac electrode diagnostics in ac-operated metal halide lamps

G.M.J.F. Luijks, H. Esveld, S. Nijdam, P.A.M. Weerdesteijn

Research output: Contribution to journalArticleAcademicpeer-review

13 Citations (Scopus)

Abstract

A diagnostic technique is presented to determine the electrode work function in ac-operated metal halide lamps. The heart of the experimental set-up is a high-speed photodiode array detector, which is able to follow real-time variations of electrode tip temperature and near-electrode plasma emissions in ac-operated experimental YAG lamps, enabling discrimination between the anode and cathode effects. Electrode tip temperature ripples have been measured for 100 Hz square wave operation and simulated with an existing electrode model. By using the electrode work function as main fit parameter for the simulations it is found that the measured cooling effect of the electrode tip in a NaTlDy-iodide lamp is caused by a gas-phase emitter effect of Dy. It is concluded that Dy coverage of the electrode tip causes an effective work function reduction of 0.3 eV at 100 Hz square wave operation, considerably less than the 1.0 eV reduction measured earlier for dc operation.
Original languageEnglish
Pages (from-to)144006-1/5
JournalJournal of Physics D: Applied Physics
Volume41
Issue number14
DOIs
Publication statusPublished - 2008

Fingerprint

Metal halide lamps
metal halides
luminaires
Electrodes
electrodes
square waves
Electric lamps
plasma electrodes
ripples
Iodides
yttrium-aluminum garnet
iodides
photodiodes
Photodiodes
discrimination
emitters
anodes
cathodes
high speed
Anodes

Cite this

Luijks, G.M.J.F. ; Esveld, H. ; Nijdam, S. ; Weerdesteijn, P.A.M. / Ac electrode diagnostics in ac-operated metal halide lamps. In: Journal of Physics D: Applied Physics. 2008 ; Vol. 41, No. 14. pp. 144006-1/5.
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Ac electrode diagnostics in ac-operated metal halide lamps. / Luijks, G.M.J.F.; Esveld, H.; Nijdam, S.; Weerdesteijn, P.A.M.

In: Journal of Physics D: Applied Physics, Vol. 41, No. 14, 2008, p. 144006-1/5.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Ac electrode diagnostics in ac-operated metal halide lamps

AU - Luijks, G.M.J.F.

AU - Esveld, H.

AU - Nijdam, S.

AU - Weerdesteijn, P.A.M.

PY - 2008

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AB - A diagnostic technique is presented to determine the electrode work function in ac-operated metal halide lamps. The heart of the experimental set-up is a high-speed photodiode array detector, which is able to follow real-time variations of electrode tip temperature and near-electrode plasma emissions in ac-operated experimental YAG lamps, enabling discrimination between the anode and cathode effects. Electrode tip temperature ripples have been measured for 100 Hz square wave operation and simulated with an existing electrode model. By using the electrode work function as main fit parameter for the simulations it is found that the measured cooling effect of the electrode tip in a NaTlDy-iodide lamp is caused by a gas-phase emitter effect of Dy. It is concluded that Dy coverage of the electrode tip causes an effective work function reduction of 0.3 eV at 100 Hz square wave operation, considerably less than the 1.0 eV reduction measured earlier for dc operation.

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