A Fluorescence Lifetime Distribution Measurement System Based on Phase-Resolved Detection Using an Image Dissector Tube

Abstract

A new phase-resolved two-dimensional fluorescence measurement system using an image dissector tube (IDT) has been developed. The gain control characteristics of the blanking electrode (located between the aperture plate and the first dynode of the IDT) are utilized to allow heterodyne detection with low-voltage control signals. Heterodyning the modulated fluorescence and reference signals at the blanking electrode of the IDT provides high-frequency response up to 1 GHz, in contrast to the 20 MHz bandwidth of the dynode chain due to electron transit time spread. Significant improvement of time resolution is observed. Fluorescence intensity and lifetime data are derived from the dc and ac components of the phase-resolved signals, respectively. Two-dimensional measurements can be performed by electronically scanning images within the IDT. Details of the instrumental system and typical fluorescence lifetime distribution measurements are presented.