Résumé
A high frequency ultrasonic sensor is designed to measure the distance between two plates in an irradiated element with access constraints. The measurement system consists in a double ultrasonic transmitter/receiver mounted on a blade in order to be inserted and manipulated into the interstice between two plates separated by about 2 mm. It operates at frequencies up to 120MHz and allows the measurement of the inter-plate distance by evaluating the time of flight of the ultrasonic waves.