Measurement of Organic Fluorescence Decay Times

Abstract

In past measurements, the decay times of scintillations produced in organic scintillators by gamma rays and the decay times of fluorescence excited by ultraviolet radiation have been determined by a self-cancellation method and a fluorometer, respectively. The results of these measurements indicated that, in general, the ultraviolet decay times were only about one-half as large as those obtained by scintillation measurements. To check the fluorometer method, the decay times of some fluorescent dyes (fluorescein, rhodamine B, and erythrosin) dissolved in glycerin were measured both by a modified version of the fluorometer and by observation of the depolarization of the fluorescence. The values thus obtained were found to agree within experimental error, which corroborated the previous observation of discrepancies between decay times derived from fluorometer and scintillation measurements.