Phased array ultrasonics (PA): is an advanced method of ultrasonic testing that has applications in medical imaging and industrial nondestructive testing. Common applications are to noninvasivelyexamine the heart or to find flaws in manufactured materials such as welds. Single-element (non-phased array) probes, known technically as monolithic probes, emit a beam in a fixed direction. To test or interrogate a large volume of material, a conventional probe must be physically scanned (moved or turned) to sweep the beam through the area of interest. In contrast, the beam from a phased array probe can be focused and swept electronically without moving the probe. The beam is controllable because a phased array probe is made up of multiple small elements, each of which can be pulsed individually at a computer-calculated timing. The term phased refers to the timing, and the term array refers to the multiple elements. Phased array ultrasonic testing is based on principles of wavephysics, which also have applications in fields such as optics and electromagnetic antennae

UT-TOFD (Time of Flight Diffraction)

The use of TOFD enabled crack sizes to be measured more accurately , so that expensive components could be kept in operation as long as possible with minimal risk of failure . The TOFD technique is a fully computerized system able to scan, store, and evaluate indications in terms of  height , length , and position with a grade of accuracy never achieved by other ultrasonic techniques . Measuring the amplitude of reflected signal is a relatively unreliable method of sizing defects because the amplitude strongly depends on the orientation of the crack, instead of amplitude, TOFD uses the time of flight of an ultrasonic pulse to determine the position of a reflector. The more accuracy guaranteed by TOFD in sizing thru wall extension of flaws allows more reliable fracture mechanic calculation for residual life evaluation