Phase and modulation fluorometer

The instrument, which is designed for the measurement of fluorescence decay times of 10-7-10-9 s, comprises a 10 Mc/s hydrogen discharge lamp, fast photomultiplier, variable delay line and detector circuit for phase and modulation analysis of light signals from the lamp and specimen. Studies have been made of the transit time variations in 56 AVP and 6810 A photomultipliers, and preliminary measurements have been made of the fluorescence decay time of quinine sulphate solutions.