Building a State of the Art Laser Diffraction Analyzer

There’s a wide gulf between bare minimum and state of the art. The latter is always the industry leader in accuracy, repeatability, usability, flexibility, and reliability. The current state of the art in laser diffraction is the Partica LA-950 featuring two high intensity light sources, a single, continuous cast aluminum optical bench (see the figure below), a wide array of sample handling systems, and expert refinements expected from the fifth revision in the 900 series.



Using two light sources of different wavelengths is of critical importance because
the measurement accuracy of small particles is wavelength dependent. Figure A (below) shows the 360° light scattering patterns from 50nm and 70nm particles as generated from a 650 nm red laser. The patterns are practically identical across all angles and the algorithm will not be able to accurately calculate the different particle sizes. Figure B (below) shows the same experiment using a 405nm blue LED. Distinct differences are now seen on wide angle detectors which allows for accurate calculation of these materials. Integrating a second, shorter wavelength light source is the primary means of improving nano-scale performance beyond the bare minimum laser diffraction analyzer.