Several crystal phosphors have been irradiated by ultraviolet wavelengths from 500 A to 1700 A. The emission spectra of all were found to be independent of exciting wavelength. The quantum efficiencies of Zn2SiO4:Mn, CaSiO3:Pb:Mn, and ZnO:[Zn], relative to sodium salicylate, increased with decreasing excitation wavelengths below 1000 A. It is suggested that this increase may be accounted for by internally emitted electrons. Several tungstate and titanate phosphors showed minima in their excitation spectra at about 1100 A, with increases for longer or shorter exciting wavelengths. Anomalous results are reported for ZnS:Ag, BaSi2O5:Pb, and Mg6As2O11:Mn.
RICHARD L. CONKLIN, "Behavior of Several Phosphors upon Irradiation in the Vacuum Ultraviolet," J. Opt. Soc. Am. 49, 669-672 (1959)