Location of focal points of focus CW ultrasonic transducers
Because of diffractive effects at the limited aperture of ultrasonic transducers, the effective focus of spherically curved-element or lensed transducers lies in front of the geometric focus defined by the radius of curvature of the element or lens, and is a function of ultrasonic frequency. This focal-point shift can be quite significant in many practical cases, and can lead to serious degradation of system performance, if not accounted for. In this work, the focal-point shift was calculated as a function of frequency and of transducer diameter. It is shown that the focal-point shift can be described in terms of the ratio d/lambda and of the transducer, lambda is the wavelength, and F is the conventional ratio of geometric focal length to effective diameter of the transducer. A nomogram relating these quantities is developed and presented.
- Research Organization:
- EG and G Idaho, Inc., Idaho Falls (USA)
- DOE Contract Number:
- AC07-76ID01570
- OSTI ID:
- 6443666
- Report Number(s):
- EGG-FM-5656; ON: DE83009933
- Resource Relation:
- Other Information: Portions are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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