| 摘要 |
PURPOSE:To enable the measurement of particle size distribution even when the number of particles is limited, by using a power storage type photo detector as such. CONSTITUTION:Monochromatic parallel beam outputted from a laser unit 1 is turned to a parallel beam 3 with a proper diameter through a lens 2 and made to irradiate particles to be measured. The light scattered by the particles 4 is received with an optical fiber 5 arranged at an angle of scattering to be measured and introduced to a storage type photo detector (71-7R). Here, a shutter 19 is arranged in front of the photo detector 7 and is opened for a proper time length depending on the number of particles, and then closed when electric charge due to the scattered light is stored sufficiently. Then, an output gate of the photo detector 7 is opened sequentially with a multiplexer to introduce the electric charge stored in the photo detector 7 sequentially to an amplifier 8, where it is converted into voltage to be amplified. In this manner, the lengthening of the observation time enables the measurement of scattered light intensity distribution even when the number of particles is limited. |
