alignment
The positioning of a sensor so that the maximum amount of the emitted sound energy reaches the receiving sensor. For pulse-echo types of sensors in object and background mode, the transmitted beam of the sensor should be perpendicular to the object or background target, respectively. For thru-beam types of sensors, alignment refers to the extent to which a line, perpendicular to the face of both transmitter and receiver, passes through the center of each face. In some situations, perfect alignment is not desirable and better results are obtained if the receiver is tilted about 10 degrees out of alignment.
