Ultrasonic power measurements in the milliwatt region by the radiation force float method

The radiation force float technique is extended in the present investigation, for the determination of the total radiated low ultrasonic power in the milliwatt region. It is elucidated, experimentally, using floats having a conical reflecting target comprising of new material (teflon insulated copper wire) stems with smaller diameters (0.55 and 1 mm). The sensitivity is improved with these two stems and the ultrasonic power levels are measured in the range from 1.4 to 140 mW and 4.6 to 460 mW respectively and the results are reproducible within +/- 5%. Limitations of float technique and factors influencing the uncertainties involved for the high quality ultrasonic power measurements are discussed. The proposed method is simple, versatile and inexpensive and can be used as an interim standard.