| 摘要 |
PURPOSE:To enable available ultrasonic calibration with respect to a conductive material, by using a calibration apparatus having an electromagnetic ultrasonic generator apparatus having a two-directional thyratron employed therein. CONSTITUTION:When an electromagnetic ultrasonic generating detector 8 is arranged on a conductive material 7 and a current is flowed through a magnetic field generating coil 10 by a D.C. power source 12, a stationary magnetic field 13 is generated in the vicinity of the surface of the material 7 by a magnetic core 9. On the other hand, when voltage V slightly lower than the natural discharge voltage of a two-directional thyratron 15 is outputted from a high voltage power source 14, a capacitor 16 is charged up to the voltage V through charging resistor 17. When the thyratron 15 is brought to a conductive state through a trigger pulse generator 18, the electric energy of the capacitor 16 is flowed into a small coil 11 to generate an eddy current 19 in the vicinity of the surface of the material 7 and ultrasonic waves accompanied by vibration force 20 are advanced to a direction shown by an arrow 21. An eddy current 24 accompanied by vibration force 23 due to reflected waves (arrow 22) thereof is detected by the coil 11 and displayed by a display device 26 through an amplifier 25 to carry out available calibration. |
