Abstract: Display of the results of non-destructive testing with a beam of ultrasonic energy is enhanced by exercising precise control over the horizontal sweep voltage which is applied to the deflection plates of a cathode ray tube on which the test information is displayed. The sweep voltage generator produces a sawtooth waveform which has a precisely selectable slope. The sawtooth voltage waveform slope may be adjusted by selecting the capacitance, which is charged from an adjustable constant current source, and by varying the charging current. A microprocessor, which stores information commensurate with various waveform slopes, will control the adjustment of the sawtooth waveform slope by comparison of the stored information with keyboard entered data corresponding to a desired slope.

Abstract: An apparatus for pumping a laser by a source of light comprises a movable housing having a plurality of cavities each containing a respective light source for pumping the laser and a laser contained in a cavity of a stationary housing. The cavity of the stationary housing forms with a respective complementary cavity of the movable housing a cylindrical pumping chamber. Responsive to the failure of a lamp, the movable housing is indexed to bring a new lamp into operative relation with the laser.

Abstract: An ultrasonic thickness measuring apparatus comprises means for developing pulse counts responsive to the transit time of the ultrasonic search signal traversing the workpiece. The accumulated pulse count is displayed after each transit time interval and is used also to derive a correction factor which is inserted into the counter accumulating the counts during each time interval. This arrangement provides for the apparatus to almost immediately display a thickness value which nearly coincides with the final measurement value.

Abstract: An ultrasonic test apparatus for testing tubes or rods by rotating transducers to provide a helical scan, the test transducer, or each of a plurality of transducers, is mounted for adjustable motion along an axis which is inclined by an angle .omega. with respect to a perpendicular axis intersecting the workpiece surface. The angle .omega. is selected to provide a desired incident angle .alpha. of the ultrasonic energy upon the workpiece surface, whereby to cause a refracted angle .beta. of the ultrasonic energy. Within the range of measuring accuracy for small angles it can be assumed that angle .omega. approximates angle .alpha..

Abstract: The acoustic energy responsive deformation of a workpiece surface is sensed in a contact-free manner by optical means using a laser which illuminates the surface at which deformation is expected. The reflection light energy is transmitted to an optical interferometer as previously shown in the art. The present improvement comprises the use of a multi-wavelength laser beam light and separating the light after passing through the interferometer into the distinct wavelengths. Each light signal corresponding to a specific wavelength is converted individually to an electrical signal, each electrical signal is rectified, and the plurality of rectified signals are then averaged in an electrical summing means.

Abstract: In an ultrasonic pulse-echo test measuring or gaging system wherein a workpiece is coupled to the ultrasonic transducer by a liquid coupling medium, the temperature of the liquid affects precise measurement of the workpiece as the acoustic velocity of a liquid changes with temperature. To compensate for the change of acoustic velocity during measurement periodically a search pulse is transmitted along its normal path over a calibrated fixed distance. The resulting transit time value is converted to a distance value and compared witht the calibrated distance value. Any difference in the values updates a compensation factor which subsequently is used in the test system. Periodic updating may be set to occur, for example, every one-half second.

Abstract: This invention relates to an interferometric laser method and apparatus for sensing the acoustic wave responsive deformation of a workpiece surface. A laser provides a coherent beam of light which after reflection at the workpiece surface is split into a first measuring beam portion and a second reference beam portion, the latter portion being delayed by being transmitted over a long delay path. The optical length of the delay path is dimensioned to be a multiple integer of the optical length of the resonator of the laser.

Abstract: A method and apparatus for producing on the surface of a workpiece free of contact with a source of energy a pulse shaped ultrasonic shock wave comprise the use of laser means. A plurality of strip-shaped equidistantly spaced surface portions of the workpiece are pulsed with coherent light from the laser means in time delayed sequence. The angle of propagation of the ultrasonic wave is determined by the center-to-center distance between the strip-shaped surface portions illuminated with coherent light, the time delay between the light pulses and the velocity of propagation of the ultrasonic wave in the workpiece.