Size Effect on Microparticle Detection

Abstract

In this paper, terahertz (THz) spectroscopy was employed to analyze compacted sand particles. The dependence of attenuation coefficient spectra on thickness was obtained. Further analysis of the spectra indicated that as the particle size increased, the attenuation coefficient of the THz spectrum also increased. The smaller sand particle samples behaved as Rayleigh particles, their extinction spectrum was mainly affected by absorption of the THz waves, thus the attenuation was small. The extinction coefficient curve of the larger particle sand samples behaved as Mie particles and exhibited the strong characteristics of a Mie scattering curve. The THz wave attenuation in the larger sand particle samples was the result of the combined effect of absorption and scattering, thus the attenuation of the THz waves was larger.