Computerized Spectrofluorometer Using Photon Counting

Abstract

A newly constructed spectrofluorometer system which is characterized by photon counting mode of detection and computer assisted operation is presented. The photon counting technique is utilized to detect a weak fluorescence emission, and the gate width of the counter is continually controlled by the monitor photomultiplier output to cancel out light source fluctuations. Correction of the spectra is carried out in real time by using correction factors derived from the results of absolute intensity measurement by means of a quantum counter. All the experimental procedures can be done in the conversational mode through a teletypewriter and the corrected and uncorrected spectra are presented on the X–Y recorder on a wavelength scale. Details of the system are described together with examples of its performance data.