Transmit-Receive (TR) probes exhibit operating characteristics which are suitable for a number of practical field inspection problems, particularly for the flaws near surface and severely attenuative materials such as austenitic stainless steel. However, due to the limitation of their structures, TR probes are only sensitive in a limited depth range. To ensure the accuracy and reliability of detection results, it's very important to confirm suitable focusing depth and effective detecting range. Because of t...