Optical absorption spectroscopy on a metal-halide high intensity discharge arc lamp using synchrotron radiation

A sensitive, spatially resolved optical absorption spectroscopy experiment using synchrotron radiation on metal-halide high intensity discharge (MH-HID) lamps was performed. This experiment was used to measure the absolute column densities of ground and excited level Sc atoms, ground level Sc + ions, and ground level Na atoms in a 250 W MH-HID lamp during operation. The column densities were Abel inverted and used to determine the arc temperature as a function of radius and the absolute electron density as a function of radius. Although most of these measurements were made using a one-dimensional spectrally-multiplexed experiment, a two-dimensional spatially and spectrally multiplexed experiment has also been demonstrated. The absolute density and temperature maps from this experiment were used to determine the absolute near-infrared output power from the MH-HID lamp as described in the companion paper (Smith et al 2003).