Effects of Ultraviolet Radiation on Fluorescent Lamp Phosphors

Abstract

Irradiation of halophosphate lamp phosphors by a low‐pressure mercury arc causes a loss in luminescent efficiency, changes in the absorption spectra, and thermoluminescence. The 1849Aå wavelength is primarily responsible for these changes, which are partially reversed by longer wavelength radiation or by heat. X‐radiation produces larger changes in the absorption spectra, which are compared to observations on unactivated halophosphates. The relation between luminescent efficiency and color center formation is discussed.