Measuring the pressure in ultrahigh-pressure mercury arcs

Hechtfischer, Ulrich; Engelbrecht, B.; Carpaij, M.; Fischer, Ernst; Koerber, A.

doi:10.1063/1.3204978

Cited by 5 publications

(6 citation statements)

References 25 publications

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“…It is turned out that the vapor pressure falls with decreasing lamp power, which reduces 40% from 258 W to 43 W. It is the immense fall of pressure that brings about the reduced continuum of plasma, ultimately resulting in poorer color rendering performance. The mercury vapor pressure is normally maintained at 20-30 MPa when the UHPs with rating power 100-200 W operate properly [5]. In this experiment, it is 15.3-25.8 MPa in lamp, which agrees with that in reference [5].…”

Section: Applied Mechanics and Materials Vols 325-326supporting

confidence: 88%

“…Effects on UHP pressure. Refer to Hechtfischer et al, the mercury vapor pressure in UHP at 100-200 W depends on the FWHM ∆λ of 546 nm, the lamp current I as well as the lamp voltage U [5]. The relationship can be expressed as follows…”

Section: Applied Mechanics and Materials Vols 325-326mentioning

confidence: 99%

“…Short arc ultra-high pressure mercury lamps (UHPs) are most widely used lamps in the projection systems currently with excellent performances such as high brightness, high efficiency, good color rendering, long life-span and steady light output, comparing to other gas discharge lamps [1][2][3]. The power of the projection system should be decreased when it temporarily stops working for the sake of power saving.…”

Section: Introductionmentioning

confidence: 99%

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Research on the Dimming Characteristics of Short Arc Ultra-High Pressure Mercury Lamps for Projection Applications

Shi

Han

Zhang

2013

AMM

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The voltage, current and power are measured for short arc ultra-high pressure mercury lamps (UHP) with rating power 250 W driven by 50 Hz square waveform power supply. It is found that the curve slope of voltage-current characteristics is positive in most of the power range, and negative around 170 W. The photometric, colorimetric and electric parameters are measured with an integrating sphere system couple with a spectrometer in UHP dimming experiments. The results show luminous flux increases with power linearly. The luminous efficacy and color rendering index (CRI) reduce with power reduction because of the decrease of spectral continuum. The mercury pressure are calculated with the full width at the half maximum (FWHM) of 546 nm spectral band, which is 6.2-11.0 nm according to the mercury pressure 15.3-25.8 MPa for UHP power 43-258 W.

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Section: Applied Mechanics and Materials Vols 325-326supporting

confidence: 88%

Section: Applied Mechanics and Materials Vols 325-326mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Research on the Dimming Characteristics of Short Arc Ultra-High Pressure Mercury Lamps for Projection Applications

Shi

Han

Zhang

2013

AMM

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“…Two approaches are (a) to measure the 1014 line emission or transmission and (b) to use measurements of the ratios of self-reversal maxima of the 313, 365 nm and 405 nm groups of lines; these ratios are very strongly dependent on pressure. Absolute calibration can be done through measurements in which the Hg vapour pressure is controlled in a side arm (Hechtfischer et al 2007). The ratios of the short wave MSR of the 313, 365 and 405 nm mercury lines, calculated using simulations based on the preferred cross-section in table 2.…”

Section: Discussionmentioning

confidence: 99%

“…To measure pressure accurately by using MSR ratios, calibration would needed. This could be done with the type of experiment reported by Hechtfischer et al (2007). They controlled the temperature of a side arm of a lamp like the one shown in figure 1, thus controlling the pressure of mercury vapour in the lamp between 150 and 300 bar.…”

Section: Pressure Measurement Based On Self-reversed Line Ratiosmentioning

confidence: 99%

Estimates of molecular absorption cross-sections in mercury plasmas at very high pressures using self-reversed line diagnostics

Wharmby¹

2008

J. Phys. D: Appl. Phys.

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Plasmas containing mercury at pressures >100 bar are used as sources of extremely high radiance. High-resolution measurements have been made of the absolute spectral radiance of a plasma in a line of sight through its centre. Detailed comparisons of the Hg 546 nm calculated line shape with measurements provide information about the pressure, centre temperature and the temperature profile. Results are given for an arc at a pressure of 160 ± 10 bar and maximum temperature of 8350 ± 100 K. Radiation transport calculations show that absorption by mercury molecules increases progressively with decreasing wavelength towards the UV. By comparing calculations of self-reversed line maxima, a temperature-independent cross-section for Hg2 absorption has been derived. Use of this, with other published data for line and continuum radiation in radiation transport calculations, yields calculated spectra in excellent agreement with the experiment except in the extreme wings of spectral lines. The calculations can be used to predict behaviour at other pressures; at all the pressures and most wavelengths considered the plasma has appreciable optical depth. Uncertainties in pressure measurement remain a problem with this type of plasma. The 313, 365 and 435 nm line radiances are absorbed to various degrees by mercury molecules. Their radiance ratios are very sensitive to pressure and could be used, if calibrated, to provide a more satisfactory measure of pressure.

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Radio frequency emission from high-pressure xenon arcs: A systematic experimental analysis of the underlying near-anode plasma instability

Hechtfischer

2011

Journal of Applied Physics

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High-pressure Xe discharge lamps at DC operation can show unwanted strong RF (radio-frequency) emission to beyond 1 GHz, correlated to a sharp periodic lamp-voltage instability in the near-anode plasma with a pulse repetition rate ε of 1–10 MHz. The physical origin of the instability is unclear. Here, its existence and pulse rate have been measured as a function of arc current I = 0.2–1.2 A and anode temperature Ta = 1700–3400 K independently, in experimental lamps with pure-tungsten electrodes and a Xe operating pressure around p = 10 MPa. Surprisingly, the instability is not affected by I or current density j but exists if Ta is lower than a threshold value around 2800–2900 K. The pulse rate ε is simply a rising linear function of the inverse anode temperature 1/Ta, with only a small I-dependent correction. The average anode heat load is slightly lower in the unstable regime and possibly depends on ε. The results allow a consistent re-interpretation of earlier and present experimental observations and should be both a valuable help in practical lamp engineering and a tight constraint for future theories of this effect.

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Measuring the pressure in ultrahigh-pressure mercury arcs

Cited by 5 publications

References 25 publications

Research on the Dimming Characteristics of Short Arc Ultra-High Pressure Mercury Lamps for Projection Applications

Research on the Dimming Characteristics of Short Arc Ultra-High Pressure Mercury Lamps for Projection Applications

Estimates of molecular absorption cross-sections in mercury plasmas at very high pressures using self-reversed line diagnostics

Radio frequency emission from high-pressure xenon arcs: A systematic experimental analysis of the underlying near-anode plasma instability

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