7 June 1989 Transient Ultrasonic Spectroscopy Using Metal Wire Explosions
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Proceedings Volume 1032, 18th Intl Congress on High Speed Photography and Photonics; (1989) https://doi.org/10.1117/12.969240
Event: 18th International Congress on High Speed Photography and Photonics, 1988, Xi'an, Shaanxi, China
A transient ultrasonic spectroscopy system has been developed using a sound pulse generated by a metal explosion and optical detection of the sound. The electric explosion of metal wire produces a short-duration acoustic pulse containing a broad Fourier frequency spectrum in the range 10 to 200 kHz. The acoustic pulse profiles at two distances are monitored by the transient photorefractive deflection of collimated probe laser beams, one of which is displaced from but parallel to the other. An angular magnification(an increase in sensitivity of detection) of the deflection is achieved by refracting the deflected laser beam through a peripheral section of a converging lens. The transient deflection is observed by using a knife-edge to block half of the probe beam and detecting the signal with a fast photodiode. By taking the difference between the electronic signal outputs of the two photodiodes, a pair of noise free transient deflection signals is recorded. Fourier analysis of these probe deflection signals provides the absorption spectrum, and an example for atmospheric air is given. The experimental results are attributed to combined absorption due to the classical effects of thermal conduction and viscosity, absorption due to rotational relaxation and due to the humidity dependent vibrational relaxation of nitrogen and oxygen.
© (1989) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Min Gon Kim, Yong Tae Kim, "Transient Ultrasonic Spectroscopy Using Metal Wire Explosions", Proc. SPIE 1032, 18th Intl Congress on High Speed Photography and Photonics, (7 June 1989); doi: 10.1117/12.969240; https://doi.org/10.1117/12.969240


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