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2-Reference Beam Profile Sensor (2REF-LDA)

(Kopie 1)

By placing two photodiodes into the beams of a cross beam type LDA one gets a simple profile sensor. For a better mapping the receivers and their associated measuring volumes as well as their signals are painted blue and green althoug the real beam colour is a single one. Depending on the trajectory of the scatterer the signals exhibit a time delay. Measuring the time-of-flight and velocity the location of passage on the optical axis of the beams can be determined by geometry. Examining more closely the phase difference of signals the size of the scattering particle can be calculated.