Topic
Acoustic interferometer
About: Acoustic interferometer is a research topic. Over the lifetime, 1493 publications have been published within this topic receiving 19355 citations.
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TL;DR: In this article, a Michelson interferometer for X-rays of wavelength ∼1 A has been proposed to test the temporal coherence of FEL radiation, based on a silicon single crystal.
Abstract: A Michelson interferometer for X-rays of wavelength ∼1 A has been proposed to test the temporal coherence of FEL radiation. Such a device has been made at HASYLAB from a silicon single crystal. It is based on the BBB interferometer of Bonse and Hart. One of its mirrors can be pushed by a piezo to introduce the desired beam path difference. For the preliminary tests described in this paper, the crystal was also equipped with an LLL interferometer to check the quality of the crystal and of its preparation. The rotation of a phase-shifting object (a Plexiglas plate) in one of the LLL's beam paths has been found to produce a fringe pattern which can be shown to yield the phase-shifting material's index of refraction. The interferometer crystal's front section was held fixed with a compression spring. At the same time, the interferometer was bathed in viscous silicone oil to reduce vibrations.
2 citations
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01 Dec 1948TL;DR: In this paper, a simplified analysis of the equivalent circuit given here is made possible by limiting the discussion to the conditions that exist when all parts of the system (electrical, mechanical, and acoustical) are adjusted to resonance.
Abstract: The ultrasonic interferometer is simple in construction and operation, and yields accurate and consistent data. From these data, one can readily determine the velocity of sound in a liquid with high accuracy. Formerly, the absorption of sound in the liquid and the coefficient of reflection at the reflector surface has been obtained through a complicated analysis of the electrical and equivalent-electrical circuits of the quartz crystal and the associated fluid column. The simplified analysis of the equivalent circuit given here is made possible by limiting the discussion to the conditions that exist when all parts of the system (electrical, mechanical, and acoustical) are adjusted to resonance. Under these conditions, the analysis of the complete electrical and equivalent-electrical circuit is greatly simplified. One does not need to analyze the shape of a reaction dip in order to obtain coefficients of absorption and reflection.
2 citations
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TL;DR: In this article, the authors investigated nonlinear sound waves from a uniformly moving source with dimensions smaller than the wavelength of the emitted sound and described spherical Burgers' equations with parameters depending on the source velocity V and the direction angle θ from the source to the point of observation.
Abstract: Nonlinear sound waves from a uniformly moving source with dimensions smaller than the wavelength of the emitted sound are investigated. They are described by spherical Burgers’ equations with parameters depending on the source velocity V and the direction angle θ from the source to the point of observation. It is seen that for certain V and θ values, both for V less than and greater than the sound velocity in the medium, shock waves occur, which do not occur in nonlinear waves from a fixed sound source.
2 citations
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TL;DR: In this article, a one-dimensional analysis of traveling acoustic waves in flows of an inviscid, nonconducting, perfect gas, containing mass and heat sources, reveals the existence of a coupling between acoustic waves and nonhomogeneous steady flow fields.
Abstract: An investigation of the interaction between acoustic waves and steady‐flow fields was stimulated by the problem of combustion instability in rocket engines. A one‐dimensional analysis of traveling acoustic waves in flows of an inviscid, nonconducting, perfect gas, containing mass and heat sources, reveals the existence of a coupling between acoustic waves and non‐homogeneous steady‐flow fields. This coupling allows energy transport between the wave and the flow field, resulting in either amplification or attenuation of the wave, depending on the gradients of the steady‐flow variables and on the propagation direction. Results of experiments with nonuniform velocity fields are in agreement with theoretical predictions. In particular, an air jet discharging into a straight organ pipe and a converging air flow through a tapered pipe, are found to attenuate waves propagating through the pipes. [This work was supported by the U. S. Air Force Office of Scientific Research.]
2 citations
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05 Oct 1998TL;DR: In this paper, the results of a theoretical investigation of simultaneous two light beams diffraction by a surface acoustic wave (SAW) in crystals are considered, and they form the theoretical basis of descriptive work of a new acoustooptic method of SAW velocity measurement based on a two optical beams interferometer.
Abstract: The results of a theoretical investigation of simultaneous two light beams diffraction by a surface acoustic wave (SAW) in crystals are considered. They form the theoretical basis of descriptive work of a new acoustooptic method of SAW velocity measurement based on a two optical beams interferometer. The influence of elastic anisotropy of a solid on the diffraction and interference of light beams and accuracy of measurement of phase and group SAW velocities in anisotropic mediums are considered. It is shown how to realize direct measurement of a SAW steering beam angle. The obtained results considerably increase possibilities of the given method for measurement of the basic characteristics of acoustic waves in crystals.
2 citations