Measurements of the Intensities of Vacuum Ultraviolet Radiation Sources using the Flow Ionization Chamber

A method for measuring the intensities of vacuum ultraviolet lamps in wavelength ranges of 105–147 nm and photon fluxes of 105–1015 photons/s is described. A flow ionization complete-absorption chamber operating under the atmospheric pressure is applied. As a working medium, a mixture of ionized volatile organic-substance vapors, methane or oxygen, and also nitrogen with a known component concentration is used. The flux value is determined from the measured ionization current, quantum ionization yield, and portion of radiation absorbed by the ionized substance.