Calibration arangement and method of calibrating an inspection instrument

Abstract

Calibration arrangement and method for calibrating an inspection instrument, such as an ultrasonic inspection instrument of the kind typically used to inspect nuclear reactor pressure vessels. The calibration arrangement comprises a frame, the frame having a slot therethrough for receiving a sonic coupling medium therein. A plurality of channels extend through the frame and are in communication with the slot. A plurality of solid reflector rods matingly extend through respective ones of the channels and into the slot for reflecting sonic energy produced by a pulsed ultrasonic transducer mounted on the frame and spanning the slot. A pulser stimulates the transducer so that the transducer transmits pulsed sonic energy through the coupling medium which resides in the slot. The sonic energy is reflected by the rods that pass through the slot. The reflected sonic energy or echoes are received by the transducer, which generates transducer output signals that are received by a receiver. The receiver provides analog output signals that are converted by an analog-to-digital converter into digital output signals. A computer connected to the analog-to-digital converter evaluates the digital output signals. A display is connected to the computer for viewing the digital output signals. The digital output signals viewed on the display are therefore indicative of the orientations of the reflector rods in the frame for calibrating the transducer with respect to the orientations of the reflector rods in the frame.