Standard Samples and Calibration Procedures,
ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
Pagination or Media Count:
A new ultrasonic calibration standard and procedure is discussed. The motivation is the calibration of ultrasonic systems for the quantitative measurement of scattering parameters. In the development, an equation is derived which relates the transmitter voltage pulse to its echo voltage pulse in a quantitative way. With the help of this equation the amplitude, angular dependence, and frequency dependence of the differential scattering cross-section may be determined for a calibration standard and compared with its invariant theoretical value and parameter dependence. A key feature of the development is the G-factor which is a proposed figure-of-merit for a transducer. The discussion includes a technique for its simple determination, and its use in the calibration procedure. The calibration standard proposed is the far-field sphere cavity or inclusion embedded in a solid or a ball suspended in a liquid. As a result of recent work, the sphere is now well understood theoretically and experimentally and is easy to incorporate into calibration standard samples.