An On-Line Spectrofluorimeter System for Rapid Collection of Absolute Luminescence Spectra

Abstract

A spectrofluorimeter system has been developed which uses an on-line general purpose digital computer to both collect and correct fluorescence and luminescence spectra; no servosystems or complex analog circuitry are employed. Spectra are represented by a series of up to 500 individual data points, each of which is, in turn, the average of 16 samplings of the signal photomultiplier. The signal produced by a reference photomultiplier is also collected and used to make corrections appropriate to the type of spectra being collected. Wavelength drive is accomplished with a reversible stepping motor driven by commands from the computer; thus the wavelength position can be automatically and precisely controlled by the computer without recourse to cumbersome mechanical components. Corrections to collected spectra are made in real time on the basis of correction factors derived from fluorescence standards or a standard lamp. The complete system can collect a full spectrum (500 points) in 8 sec, average the results of any number of automatically repeated scans, and furnish the operator with both corrected and uncorrected spectra on either a wavelength or a wavenumber scale. In addition, the data can be retained on punched paper tape or presented graphically in a format acceptable for publication. Details of the system are presented with examples of its performance.