What is another name for the Fresnel Zone in ultrasonic testing?

In ultrasonic testing, the Fresnel Zone is commonly referred to as the Near Field. This region exists close to the transducer and is characterized by rapidly changing sound wave patterns due to the interference between the waves emanating from the ultrasonic transducer. Within the Near Field, the sound waves do not propagate uniformly, which can result in a complex distribution of sound intensity.

The significance of understanding the Near Field is that it affects measurement accuracy and the interpretation of collected data. As the angle and distance from the transducer vary within this zone, the sound intensity can vary unpredictably, which is crucial for technicians to consider when positioning the transducer and during data analysis.

In contrast, the other options like the Far Field, Shadow Zone, and Reflection Zone refer to different regions or phenomena associated with ultrasonic wave propagation and behavior. The Far Field, for instance, is the region where the sound waves have stabilized, and the intensity becomes more predictable. Shadow Zones are areas behind an object where sound waves are blocked or significantly reduced due to diffraction and scattering, while the Reflection Zone typically refers to areas where waves reflect off surfaces, often leading to echoes and secondary reflections. These concepts are distinct from the characteristics defined in the Near Field/Fresnel Zone.