An ultrasonic probe (also known as a tool head or horn) is an accessory that acts as a mechanical amplifier, increasing the amplitude of the vibrations generated by the transducer.
When driven at its resonant frequency, the ultrasonic probe expands and contracts longitudinally. This mechanical vibration is amplified and propagated along the length of the probe. In liquids, the probe induces cavitation, the primary mechanism of sample processing. The distance the probe moves is measured as the amplitude. A greater mass ratio between the upper and lower sections increases the amplification factor and the peak-to-peak excursion of the probe tip. The amplitude setting can be adjusted on the power supply.
Probes with smaller tip diameters produce greater cavitation intensity, but the released energy is confined to a narrower, more concentrated volume. Conversely, probes with larger tip diameters produce less intensity but release energy over a wider area. A larger tip diameter allows for larger volumes to be processed, but the intensity is lower.
