Versatile Technique for Measuring Fluorescence Decay Times in the Nanosecond Region

Abstract

A new method of accurately recording scintillation pulse contours over several decades is described. Scintillation pulses are analyzed by an apparatus which combines the very fast rise time of a pulse sampling oscilloscope and the digital storage capacity of a multichannel analyzer. A special feature of this technique is its ability to accept, within limits, pulses random in time and amplitude so that fluorescence from samples excited either by pulsed uv radiation, β, or α particles may be analyzed. This apparatus, in combination with a hydrogen flash tube and a monochromator, has been used to measure the decay time of fluorescent solutions as a function of the wavelength of the exciting radiation. Decay time measurements have also been made for various modes of excitation: α particle, β particle, and pulsed uv.