Imaging Laser Absorption Spectroscopy of the metal-halide lamp in a centrifuge (1–10g)

Imaging Laser Absorption Spectroscopy (ILAS) was performed on a metal-halide lamp under hyper-gravity conditions in a centrifuge (acceleration ranging from 1 to 10 g ). Diffusive and convective processes in the arc discharge lamp cause an unwanted non-uniform distribution of the radiating metal additive, which results in colour separation. Convection is induced by gravity, and measuring under different apparent gravity conditions aids the understanding of the flow processes in the lamp. The centrifuge was built to investigate the lamp under varying apparent gravity conditions. The metal additive density distribution in the lamp is measured by ILAS. In this novel diagnostic technique the laser beam is expanded, so the absorption in the complete plasma volume is imaged simultaneously.