Light measuring apparatus

Abstract

Apparatus usable as a fluorometer for measuring the concentration of fluorescent material in a specimen employs a flashing lamp to illuminate the specimen with excitation radiation. The intensity of the fluorescence emitted by the specimen is therefore modulated at the flash rate. That modulated fluorescence is converted by a photodetector to an electrical signal. The electrical signal is amplified and is passed through a phase sensitive detector to an integrator. The phase sensitive detector is regulated to operate at a rate related to the flash rate whereby an appropriately rectified signal is fed to the integrator. When the specimen has been subjected to a selected amount of excitation radiation, a signal is generated which marks the end of the integration interval. The accumulated signal in the integrator is then measured to obtain a measurement of the quantity of fluorescent material in the specimen. The apparatus is also usable as a nephelometer to measure the light scattering properties of a specimen illuminated by the flashing lamp.

Dependencies are inferred from the claim text.