Fig. 1. (a) Typical optical structure of laser particle size analyzer; (b) structural schematic of traditional sample cell

Fig. 2. (a) Schematic of multiple beams; (b) schematic of trapezoidal sample cell; (c) schematic of prism sample cell; (d) schematic of cylindrical-lens sample cell

Fig. 3. (a) Propagation schematic of beams parallel to paper in laser particle size analyzer based on annular sample cell; (b) propagation schematic of incident rays and refractive rays parallel to paper within annular sample cell

Fig. 4. Propagation schematic of scattering light from particles at off-center position within sample cell

Fig. 5. (a) Light energy distributions corresponding to typical particle sizes, gray region is range of scattering angle unreceived by traditional sample cell; (b) ERMS versus α

Fig. 6. Schematic of reflection inside annular sample cell with blackened ektexine

Fig. 7. Experimental setup with annular sample cell

Fig. 8. Measurement results of Duke standard particles. (a) 50 nm; (b) 100 nm; (c) 200 nm; (d) 400 nm; (e) mixed 100 nm and 200 nm particles; (f) mixed 200 nm and 400 nm particles