New wide-range thermal ultrasound intensity sensor concept using a half-bridge-circuit for temperature sensoring

The thermo acoustic sensor measures ultrasound field intensities by evaluating the warming of an absorber material. In the range of medical used ultrasound intensity there is a linear dependency between intensity and absorber warming. By using different absorber materials the sensitivity of the sensors can be influenced. Several materials were tested to make the absorber most sensitive. In addition to sensitivity measurements, measurements of linearity, response time and spatial resolution were performed for all sensors. Transfer functions between temperature differences and intensities were evaluated. Furthermore investigations on sensors with nonmetal housings show an increase in sensitivity. Combining materials and housings enables sensors for several intensities. A new sensor concept containing a half-bridge measurement circuit improves the evaluation and leads to handy and user- friendly intensity measurement applications in future.