BASIC AND PRACTICAL CONSIDERATIONS IN UTILIZING PHOTON COUNTING FOR QUANTITATIVE SPECTROCHEMICAL METHODS

A relatively simple inexpensive photon counting system is described that can be connected to the output of photomultiplier tubes, including the popular 1P28 tube. The basic and practical characteristics of the system are presented to illustrate that photon counting can be made widely applicable with significant advantages for all types of spectrophotometry including absorption, fluorescence, emission, and scattering methods. Compared to other measurement systems the important advantages provided directly or indirectly by the photon counting method are direct digital processing of the inherently discrete spectral information, decrease of effective dark current by orders of magnitude, improvement of signal-to-noise ratio, sensitivity to very low light levels, accurate signal integration, improved precision of analytical results, elimination of reading error, and better spectral resolution. Each of these advantages is discussed in relation to the basic phenomena inherent in photon counting. © 1969, American Chemical Society. All rights reserved.