The backing material helps damping the ringing of the crystal and absorbs the ultrasound waves emitted around the crystal.
- The waves emitted by the top and side of the crystal are absorbed by the damping material
- With a low damping material, the crystal continues to ring producing several waves
- With a high damping material, the crystal only produces one wave
The damping material gives very specific characteristic to the probe and must be chosen very carefully by the probe manufacturer.