| 摘要 |
A device and process for interferometric sizing of stochastic (irregular and/or inhomogeneous) particles is disclosed. The device generates a pair of laser beams that interfere with one another to form a measuring volume including interference fringes. Particles crossing the fringes scatter light collected by two or more optical receivers. Outputs of the optical receivers are provided to signal processing and phase processing circuits, to generate indications of particle velocities based on signal frequencies, and indications of particle sizes based on phase shift values. Particles are characterized as to size by generating probability density functions of phase, based on multiple particle traverses through the measuring region, thus to more accurately measure groups of particles, despite the lack of reliability inherent in measuring a single particle. The device is operable in a calibration mode, using particles of known sizes or size distributions. In the calibration mode, phase processing circuitry uses the known particle size distributions and the measured phase distributions to determine certain coefficients which are stored in the phase processing circuitry. These coefficients are later used to generate size distribution functions, based on phase distribution functions obtained by measuring multiple phase values generated by stochastic particles of unknown size.
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