Investigating the dependence of the temperature of high-intensity discharge (HID) lamp electrodes on the operating frequency by pyrometric measurements

Reinelt, Jens; Westermeier, M; Ruhrmann, C; Bergner, Andreas; Awakowicz, Peter; Mentel, J.

doi:10.1088/0022-3727/44/9/095204

Cited by 14 publications

(24 citation statements)

References 41 publications

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“…Reliable results were obtained with this method for electrodes operated with a dc-current [1,6,11]. But if the electrodes are operated with an ac-current the modulation of the electrode temperature is limited to a small area behind the electrode tip [15]. Therefore also the tip region with its exaggerated values of has to be taken into account when the integral of the heat balance is matched to the measured temperature distribution.…”

Section: Pyrometric Electrode Temperature Measurement (1λ-method)mentioning

confidence: 99%

“…In this case it is easier to identify and remove locally excessive temperatures. A detailed discussion of the limited measuring accuracy of T tip is presented in [15,26]. It was shown that the phase resolved experimental determination of T tip is afflicted with an error of the order of ∆T tip ≈ 50 K.…”

Section: Pyrometric Electrode Temperature Measurement (1λ-method)mentioning

confidence: 99%

“…By an inverse Abel transformation of I L (y) radial emission coefficients L (r) are obtained if the discharge is rotational symmetric. Table 4: Spectroscopic data for the calculation of the plasma temperature T pl from Hg-line intensities [38] At first the plasma temperature T pl inside a YAG lamp is determined using two overlapping mercury lines at λ 1 = 576.96 nm and λ 2 = 579.07 nm [15,24,37]. The corresponding spectroscopic data is given in table 4 with the transition probabilities A 1 and A 2 , the statistical weights g 1 and g 2 and the excitation energies of the upper line levels E 1 and E 2 .…”

Section: Emission Spectroscopymentioning

confidence: 99%

“…If pure tungsten electrodes are used the temperature of the electrode tip is raised up to its melting point, T m = 3695 K, to supply a sufficiently high thermionic electron emission for a diffuse attachment of the lamp arc on the electrodes [9,10,11,12,13,14,15]. But the work function and with it the electrode temperature can be substantially reduced if a dipole layer consisting of a monolayer of atoms being electropositive with respect to tungsten is deposited on the tungsten surface.…”

Section: Introductionmentioning

confidence: 99%

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Investigating the gas phase emitter effect of caesium and cerium in ceramic metal halide lamps in dependence on the operating frequency

Ruhrmann¹,

Westermeier²,

Bergner³

et al. 2011

J. Phys. D: Appl. Phys.

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HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Abstract. The work function and with it the temperature of tungsten electrodes in HID lamps can be lowered and the lifetime of lamps increased by the gas phase emitter effect. A determination of the emitter effect of Cs and Ce is performed by phase resolved measurements of the electrode tip temperature T tip (ϕ), plasma temperature T pl (ϕ) and particle densities N (ϕ) by means of pyrometric, optical emission and broadband absorption spectroscopy in dependence on the operating frequency. The investigated HID lamps are ceramic metal halide lamps with transparent discharge vessels made of YAG, filled with a buffer gas consisting of Ar, Kr and predominantly Hg and seeded with CsI or CeI 3 . In the YAG lamp seeded with CsI and CeI 3 as well as in a YAG lamp seeded with DyI 3 (corresponding results can be found in a preceding paper) a gas phase emitter effect is observed in the cathodic phase due to a Cs, Ce or Dy ion current. In the YAG lamp seeded with CsI the phase averaged coverage of the electrode surface with emitter atoms decreases and the electrode temperature rises with increasing frequency, whereas the emitter effect of Ce and Dy is extended to the anodic phase, which leads to a decreased average temperature T tip (ϕ) with increasing frequency. This different behaviour of the averaged values of T tip (ϕ) for increasing frequency is caused by the differing adsorption energies E a of the respective emitter materials. In spite of the influence of E a on the coverage of the electrode with emitter atoms, the cathodic gas phase emitter effect produces in the YAG lamps seeded with CsI, CeI 3 and DyI 3 a general reduction of the electrode tip temperature T tip (ϕ) in comparison to a YAG lamp with Hg filling only.

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Section: Pyrometric Electrode Temperature Measurement (1λ-method)mentioning

confidence: 99%

Section: Pyrometric Electrode Temperature Measurement (1λ-method)mentioning

confidence: 99%

Section: Emission Spectroscopymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Investigating the gas phase emitter effect of caesium and cerium in ceramic metal halide lamps in dependence on the operating frequency

Ruhrmann¹,

Westermeier²,

Bergner³

et al. 2011

J. Phys. D: Appl. Phys.

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“…The behaviour of tungsten electrodes for HID lamps was investigated recently in the so called Bochum model lamp filled with argon [6] in dependence on the operating frequency being varied between 10 Hz and 10 kHz [28]. The Bochum model lamp is formed by a quartz tube, sealed vacuum-tight by two metallic end pieces with feedthroughs containing movable holders for the tungsten electrodes.…”

Section: Introductionmentioning

confidence: 99%

Investigating the influence of the operating frequency on the gas phase emitter effect of dysprosium in ceramic metal halide lamps

Reinelt¹,

Westermeier²,

Ruhrmann³

et al. 2011

J. Phys. D: Appl. Phys.

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To cite this version:J Reinelt, M Westermeier, C Ruhrmann, A Bergner, G M J F Luijks, et al.. Investigating the influence of the operating frequency on the gas phase emitter effect of dysprosium in ceramic metal halide lamps. Journal of Physics D: Applied Physics, IOP Publishing, 2011, 44 (22) Abstract. The dependence of the gas phase emitter effect of Dy on a variation of the operating frequency between some Hz and 2 kHz is investigated in a HID lamp. The buffer gas of the lamp consisting of Ar, Kr and predominantly Hg is seeded with DyI 3 , its burner vessel is formed from transparent YAG material. Phase and spatial resolved emission spectroscopy in front of the lamp electrode and pyrometric temperature measurements along the tungsten electrode are performed with a spectroscopic set up. Dy atom and ion densities in front of the electrode are deduced from absolute intensities of optically thin Dy lines and a plasma temperature, derived from the absolute intensity of mercury lines. Phase resolved values of the electrode tip temperature T tip and input power P in are obtained from temperature distributions along the electrode. Distinctly higher Dy ion and atom densities are measured in front of the electrode within the cathodic phase. With increasing operating frequency a reduction of both, atoms and ions, is observed in front of the cathode. In contrast, an increase of the ion density in front of the anode is seen. Moreover, the Dy ion density is drastically reduced by an additional seeding of the lamp with T lI. It is found that an up rating of the Dy ion density is correlated with a decline of T tip and P in . At higher frequencies this effect takes place not only within the cathodic phase but also within the anodic phase. The reduction of the average electrode tip temperature on the order of several hundred Kelvin compared to a YAG lamp with a pure mercury filling is explained by a Dy monolayer on the electrode surface which is sustained by a Dy ion current.Submitted to: J. Phys. D: Appl. Phys.Investigating the influence of the operating frequency on the gas phase emitter effect of Dy2

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The gas phase emitter effect of lanthanum within ceramic metal halide lamps and its dependence on the La vapor pressure and operating frequency

Ruhrmann

Hoebing

Bergner

et al. 2015

Journal of Applied Physics

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The gas phase emitter effect increases the lamp lifetime by lowering the work function and, with it, the temperature of the tungsten electrodes of metal halide lamps especially for lamps in ceramic vessels due to their high rare earth pressures. It is generated by a monolayer on the electrode surface of electropositive atoms of certain emitter elements, which are inserted into the lamp bulb by metal iodide salts. They are vaporized, dissociated, ionized, and deposited by an emitter ion current onto the electrode surface within the cathodic phase of lamp operation with a switched-dc or ac-current. The gas phase emitter effect of La and the influence of Na on the emitter effect of La are studied by spatially and phase-resolved pyrometric measurements of the electrode tip temperature, La atom, and ion densities by optical emission spectroscopy as well as optical broadband absorption spectroscopy and arc attachment images by short time photography. An addition of Na to the lamp filling increases the La vapor pressure within the lamp considerably, resulting in an improved gas phase emitter effect of La. Furthermore, the La vapor pressure is raised by a heating of the cold spot. In this way, conditions depending on the La vapor pressure and operating frequency are identified, at which the temperature of the electrodes becomes a minimum.

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Investigating the dependence of the temperature of high-intensity discharge (HID) lamp electrodes on the operating frequency by pyrometric measurements

Cited by 14 publications

References 41 publications

Investigating the gas phase emitter effect of caesium and cerium in ceramic metal halide lamps in dependence on the operating frequency

Investigating the gas phase emitter effect of caesium and cerium in ceramic metal halide lamps in dependence on the operating frequency

Investigating the influence of the operating frequency on the gas phase emitter effect of dysprosium in ceramic metal halide lamps

The gas phase emitter effect of lanthanum within ceramic metal halide lamps and its dependence on the La vapor pressure and operating frequency

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