title: A differential amplifier circuit for reducing noise in axial light loss measurements.
abstract: Simplified electronics have been developed for reducing laser excitation source light intensity fluctuations in flow cytometric axial light loss (extinction) measurements. By continuously monitoring the laser output with a photodiode detector and combining it with the axial light loss signal from a second detector using a high-speed differential amplifier, background interference is reduced 10 to 40 dB. Oscilloscope waveforms and frequency distribution histograms recorded from uniform-size polystyrene latex spheres and human mononuclear blood cells are used to illustrate the noise reduction capabilities.
mesh_terms: D000669:Amplifiers, Electronic; D005434:Flow Cytometry / Q000379:methods*; D006801:Humans; D007834:Lasers; D008863:Microspheres; D009000:Monocytes / Q000166:cytology