METHOD AND APPARATUS FOR ANALYZING GRANULAR MATERIAL

摘要

PURPOSE:To eliminate the fluctuation in the intensity of acoustic waves and to obtain exact and reliable information by detecting the acoustic waves generated by irradiation of a 1st beam and a 2nd beam by a piezoelectric element. CONSTITUTION:Light oscillated by a light source 3 is branched to two beams by using a half mirror 4. The beam 1 after branching is set with the intensity of the light or energy density higher than the breakdown threshold of a particle and lower than the breakdown threshold of a medium in order to cause the breakdown of the particle. The beam 2 is set with the energy density lower than the breakdown threshold of the particle with the plasma generated by the beam 1. After the beams are converged by lens 6, the focuses are aligned and a sample is irradiated with these beams in a cell 7 in which the sample is packed. The acoustic waves generated by the irradiation of the beams 1, 2 are then detected by the piezoelectric element 8 and are converted to electric signals. The signals are then subjected to a signal processing 9 and the pulse light distribution of the resulted acoustic waves is recorded 10.