This Phased Array Calibration Block designed by Paul Holloway of Holloway NDT & Engineering contains all of the required features of the ASME Sec V Art 4 Basic Calibration Block for non-piping applications, yet spaces the holes out on a longer, narrower block. The block contains two holes at 3/32″ diameter drilled through the 1.500″ width, located at 1/2T and 3/4T.
This block is designed to reduce echo interference when performing a DAC/TCG calibration. The 1/2T hole is isolated from all other reflectors, while the 1/4T hole doubles as the 3/4T with the block inverted. A 150° angle has also been machined into the block ends to diminish corner reflections. As a result, the 1/2T hole signal is free of other reflection sources to sound path distances exceeding 6 inches.