Author(s): Mark S. Kaminski, Kevin J. Garcia, Michael Stevenson, Michael Frate, R. John Koshel
Techniques to improve source modeling are presented: filament flux weighing, depositions on the arc envelope interior, and electrode degradation. Filament sources provide more light from the center in comparison to the ends. Additionally, the helix interior is hotter due to increased absorption, and thus the flux emission is greatest here. These effects for linear filaments are modeled in software with the ancillary use of camera images of lit appearance. The result is that the source luminance is more accurately modeled. This technique, called flux weighting, is described and software examples using reflectors are presented and compared to those that do not use flux weighting. Software models of arc sources that employ camera images of the arc provide accurate representations of the source radiance. However, these models do not include arc source aging. Aging effects include degradation of the electrodes and the depositions on the interior of the envelope. These phenomena lead to a decrease typically in the luminance from the source. Camera images of the lit and unlit appearance of arc sources are presented and their effect on the arc output is discussed. Additionally, software examples using reflectors are presented and compared to those that do not use these techniques.
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