Spectral irradiance model for tungsten halogen lamps in 340–850 nm wavelength range

Abstract

We have developed a physical model for the spectral irradiance of 1 kW tungsten halogen incandescent lamps for the wavelength range 340-850 nm. The model consists of the Planck's radiation law, published values for the emissivity of tungsten, and a residual spectral correction function taking into account unknown factors of the lamp. The correction function was determined by measuring the spectra of a 1000 W, quartz-halogen, tungsten coiled filament (FEL) lamp at different temperatures. The new model was tested with lamps of types FEL and 1000 W, 120 V quartz halogen (DXW). Comparisons with measurements of two national standards laboratories indicate that the model can account for the spectral irradiance values of lamps with an agreement better than 1% throughout the spectral region studied. We further demonstrate that the spectral irradiance of a lamp can be predicted with an expanded uncertainty of 2.6% if the color temperature and illuminance values for the lamp are known with expanded uncertainties of 20 K and 2%, respectively. In addition, it is suggested that the spectral irradiance may be derived from resistance measurements of the filament with lamp on and off.

The inclusion of source effect consideration in irradiance determination

“…Since the form and the intensity of radiation from lamp filament could be affected due to thermal expansion of lamp filament, transmittance through the gas inside lamp bulb and glass envelope, for a complete characterization of irradiance we expressed the irradiance as a function of all these parameters as given in Eq. (4) [9].…”

“…In some works, mainly lamp filament's emissivity was taken either constant within the filters band pass [6,7] or its wavelength behavior was estimated with the polynomial fitting of measured values of filter radiometer to calculated values [8]. In some of the recently published studies, effects of the emissivity and related parameters on irradiance have also been examined [9].…”

Development of Methods of Realization and Dissemination of the Units of Spectroradiometry with the Use of Synchrotron Radiation

“…The use of the synchrotron radiation of electron storage rings provides new resources for the development of fundamental and applied spectroradiographic studies related to increasing precision in realization of the units of spectroradiography by means of the fundamental physical constants as well as to the dissemination of the units to secondary standard radiation sources, fi lter radiometers, and spectroradiometers. The dissemination of the unit of the spectral density of irradiance is accompanied by a number of essential diffi culties, chief among which are scattered radiation and luminescence and degradation of the receivers under the effect of short-wave ultraviolet radiation [1][2][3][4][5].Studies of the spectral density of the irradiance of secondary standards of radiation sources, including hydrogen, deuterium, xenon, and thermal radiation sources, with the use of a standard source of synchrotron radiation in the working spectral range corresponding to the range of wavelengths much greater than the critical wavelength of synchrotron radiation were performed. A comparator that comprises a double monochromator and cooled CCD array by means of which signals…”

“…The use of the synchrotron radiation of electron storage rings provides new resources for the development of fundamental and applied spectroradiographic studies related to increasing precision in realization of the units of spectroradiography by means of the fundamental physical constants as well as to the dissemination of the units to secondary standard radiation sources, fi lter radiometers, and spectroradiometers. The dissemination of the unit of the spectral density of irradiance is accompanied by a number of essential diffi culties, chief among which are scattered radiation and luminescence and degradation of the receivers under the effect of short-wave ultraviolet radiation [1][2][3][4][5].…”

“…With the use of an expansion into a Taylor series with respect to the small parameter c 2 (T s -T i )/(λT s T i ), we may write (5) as…”