Through & pulse echo transmission ultrasonics

For the ultrasound techniques, internal damage is detected by the attenuation or reflection of 1-25MHz ultrasonic waves. The selection of which technique to use (through transmission or pulse echo) depends on the accessibility of the surfaces of the component. The C-scan technique is one of the most useful techniques available. Here, the relative attenuation of ultrasonic waves across a component surface creates a plan view of any damage contained within the component. Some systems requires components to be removed from structures and immersed in a water bath which acts as a medium for ultrasonic transmissions. Other systems allow the component to be examined without being removed.