| abstract |
A luminescence measuring system is provided for detecting luminescence at extremely low concentrations of luminescing moieties. The method employs alternating radiation at a plurality of loci of an inhomogenous solution, where the radiant power is maintained constant, and the irradiated volumes of pairs of loci are systematically varied. With the probability being very low that the same luminescence signal will be obtained in the two or more measurements, by comparing the measurements, one can detect a low luminescence signal in the presence of relatively high noise levels. Various techniques are described for modulating the irradiance and detecting changes in signal. |