Absolute Quantum Efficiency of Sodium Salicylate for Excitation by Extreme Ultraviolet

The absolute quantum efficiency of sodium salicylate has been measured for incident uv in the wavelength range 304 to 1216 Å. A simple model for the radiative transfer within a thin phosphor screen is used to correct the results for incomplete absorption of the incident uv and for self absorption of the luminescent flux. The model also predicts the variation of screen response with thickness. The measurements indicate a value of about 45% for the quantum efficiency in the short-wavelength plateau of the excitation spectrum.