Title :
A high-sensitivity particle monitor using an integration sphere
Author :
Watanabe, Kenzo ; Yamaguchi, Tomuo ; Nakayama, Masakatsu ; Gao, Yi-Zhu ; Nagasawa, Tadashi ; Ozawa, Taiyo
Author_Institution :
Res. Inst. of Electron., Shizuoka Univ., Hamamatsu, Japan
fDate :
6/1/2000 12:00:00 AM
Abstract :
A particle monitor is developed for real-time measurement of dust concentration measured in living and working environments. The principle of the device is based on the optical scattering method. An integration sphere is used to collect the light scattered by dust onto a photo-detector (PD). A double-modulated laser system, a low-noise current-to-voltage converter and a synchronous demodulator for averaging are used for the optical source and detector, respectively, to enhance the signal-to-noise ratio (SNR). Individual performances of the optical and signal processing units indicate that a dust concentration lower than 0.2 μg/m3 is detectable, but the minimum detectable concentration of an assembled prototype monitor is limited to 5 μg/m 3. This may be due to diffracted light and optical misalignment
Keywords :
air pollution measurement; computerised monitoring; dust; light scattering; measurement by laser beam; optical information processing; signal processing equipment; SNR; averaging; current-to-voltage converter; diffracted light; double-modulated laser; dust concentration; high-sensitivity particle monitor; integration sphere; light scattering; living environment; optical misalignment; optical processing; optical scattering; photodetector; real-time measurement; signal-to-noise ratio; synchronous demodulator; working environment; Assembly; Demodulation; Light scattering; Monitoring; Optical detectors; Optical scattering; Optical signal processing; Particle measurements; Particle scattering; Signal to noise ratio;
Journal_Title :
Instrumentation and Measurement, IEEE Transactions on
