Imaging laser absorption spectroscopy of the metal-halide lamp under hyper-gravity conditions ranging from 1 to 10g

The metal-halide (MH) lamp shows an unwanted non-uniform distribution of the metal additive (Dy in our case), caused by convection and diffusion phenomena. MH lamps with various Hg pressures and burner lengths have been investigated by imaging laser absorption spectroscopy under varying gravity conditions in a centrifuge (1-10g). 2D ground state Dy density profiles have been determined. From these images, the density inhomogeneity and corrected axial segregation parameters are obtained. The profiles and parameters are affected by the axial temperature gradient, which is more pronounced for higher Hg pressures and shorter burner lengths.