| 摘要 |
PURPOSE: To provide an ultrasonic inspection apparatus by which the existence of a cavity, impurities and other flaws can be inspected even in a sample in which ultrasonic waves at a high frequency are attenuated immediately. CONSTITUTION: The exciting energy of the output of a laser 10 for ultrasonic generation is lowered by setting a pulse width at about 100 to 200ns. A laser beam 11 is amplified by a laser amplifier 12 in a state that the pulse width has been maintained, and it is output. Consequently, the amplified laser beam 11 has a wide pulse width and a sufficient intensity. When the laser beam 11 is emitted to a sample surface 16, ultrasonic waves at a low frequency of about 1 to 2MHz are generated. The ultrasonic waves at the frequency of this extent are propagated easily even in a sample such as a slab or a molten ore in which ultrasonic waves at a high frequency of about 10 to 20MHz are hard to propagate, and the sample can be examined as an object. |
