Apparatuses and methods for measuring and characterizing ultrasound using thermoacoustic sensors are provided. Thermoacoustic sensors can include heat flux sensors for detecting a temperature difference (between the front and back of the heat flux sensor) and an absorber layer attached to the heat flux sensor for absorbing ultrasound, converting it to heat, and also acting as an acoustic impedance matching layer. An heat sink can also be used. In some embodiments, thermoacoustic sensors can be arranged into an acoustic integrating sphere and face inward to form a cavity. The sphere can have an opening to the cavity, wherein ultrasound emitted through the opening can cause a temperature difference that can be detected by the thermoacoustic sensors. These apparatuses and others can provide for methods of measuring ultrasound power and/or methods of determining an ultrasound profile as the angular distribution of emitted ultrasound power generated by an ultrasound transducer.
