A simple Δλ-method for routine measurements of atomic partial pressures in burning hid lamps

The well-known "Deltalambda-method" relating the distance of the self-reversal maxima Deltalambda of atomic lines and the summed elemental pressure p(X) has been considerably simplified because it was recognised that the Deltalambda(p(X))-relationship becomes extremely simple if Deltalambda < 5 A. Therefore, highly-resolved spectra can be used to determine summed partial pressures of dosed elements or impurities in HID lamps. A clear criterion serves for selection of suitable atomic lines. Calibration is also easy since only one proportionality constant has to be determined. The method has been tested to work properly for determining the partial pressures of Sri, Hg, Hf, Ti, Al and Y in lamps with several bars of mercury as buffer gas. It also might be very useful to improve thermodynamical models of salt melts in HID lamps with comparatively little experimental effort.