A PC based photo-acoustic instrumentation system

Author

Greig, F. ; Johnston, E.M. ; Binnie, T.D. ; MacKenzie, H.A.

Volume

3

fYear

1994

fDate

Oct. 31 1994-Nov. 3 1994

Firstpage

1333

Abstract

The development of a compact real-time photoacoustic system is described. The system is designed to measure hydrocarbon concentration levels in the range 0-200 ppm in oil industry process discharge water. A developmental system using the output from a Q switched Nd:YAG laser, frequency shifted using Raman scattering and a monochromator, allows spectral measurements in the range 1-2 μm to be made. A PC controlled acquisition system, with a 25 MHz sample rate, is used to automate the measurements and subsequent data analysis. The raw photo-acoustic signal is immersed in random noise and the fast acquisition system enables 4096 samples to be taken within the pulse repetition rate to obtain an adequate signal to noise ratio in real-time. Programmable electronics have been developed to reduce the digitisation errors to less than 0.5%. Further off line analysis using neural networks demonstrates the potential of the technique

Keywords

chemical variables measurement; data acquisition; infrared spectroscopy; microcomputer applications; neural nets; oil technology; photoacoustic spectroscopy; spectrochemical analysis; spectroscopy computing; water pollution measurement; 1 to 2 micron; 25 MHz; PC based photoacoustic instrumentation system; PC controlled acquisition system; Q switched Nd:YAG laser; Raman scattering; YAG:Nd; YAl5O12:Nd; compact real-time photoacoustic system; data analysis; developmental system; digitisation errors; fast acquisition system; hydrocarbon concentration levels; monochromator; neural networks; off line analysis; oil industry process discharge water; programmable electronics; pulse repetition rate; random noise; raw photo-acoustic signal; real-time; signal to noise ratio; spectral measurements; Data acquisition; Infrared spectroscopy; Microcomputer applications; Neural network applications; Petroleum industry; Photoacoustic spectroscopy; Water pollution;

fLanguage

English

Publisher

ieee

Conference_Titel

Ultrasonics Symposium, 1994. Proceedings., 1994 IEEE

Conference_Location

Cannes, France

Print_ISBN

0-7803-2012-3

Type

conf

DOI

10.1109/ULTSYM.1994.401838

Filename

401838