A new radiation force balance for acoustic power measurement of ultrasonic phased array

The ultrasonic phased array has been used for research and application of focused ultrasonic treatment for at least 20 years. However, due to the complexity of its working modes, there is still lack of simple convenient and effective method to measure the acoustic power transmitted by the phased array. In this paper, a new radiation force balance (RFB) method based on a absorbing target of convex spherical segment is proposed for measuring the output acoustic power of the array. The measurement principle, system and procedures of this method are described, and the ratio r=P/cF for various combinations of array elements is derived, where c is speed of sound in water, P is the output acoustic power and F is the axial radiation force acting on the target, which provides a basis of designing and applying the measurement system.