Acoustic pulse echo measurements at 200 MHz

1977 ◽  
Vol 30 (2) ◽  
pp. 78-80 ◽  
Author(s):  
B. T. Khuri‐Yakub ◽  
G. S. Kino
Keyword(s):  
Acoustic Pulse ◽  
Pulse Echo

scholarly journals THE STUDY OF THE INFLUENCE OF X-RAY IRRADIATION ON DISLOCATION CHARACTERISTICS IN LiF CRYSTALS

2021 ◽  
pp. 21-25
Author(s):  
О.M. Petchenko ◽  
G.О. Petchenko ◽  
S.M. Boiko ◽  
А.S. Litvinenko
Keyword(s):  
Irradiation Time ◽  
Acoustic Pulse ◽  
Residual Deformation ◽  
Ultrasound Velocity ◽  
Wide Frequency Range ◽  
Effective Length ◽  
Acoustic Characteristics ◽  
Frequency Branch ◽  
Attenuation Mechanism ◽  
Pulse Echo

The dependences of the absorption α and the ultrasound velocity in LiF single crystals with residual deformation ε = 0.65% at 300 K in the range of radiation doses 0...1057 R were studied using the acoustic pulse echo method at a frequency of 7.5 MHz. Based on the results of measurements of the acoustic characteristics, the absolute values of the parameters of the dislocation structure – the average effective length of the dislocation loop L and the dislocation density Λ and their dependences on the irradiation time are determined. The calculated characteristics are compared with the previously obtained results for the high-frequency branch of the damped dislocation resonance and using the selective etching method. The revealed noticeable discrepancy in the values of these parameters is explained by the impossibility of describing a single attenuation mechanism for acoustic measurements carried out in a wide frequency range.

Ultrasonic Reflectivity Imaging in Three Dimensions: Reconstruction with Spherical Transducer Arrays

1979 ◽  
Vol 1 (3) ◽  
pp. 210-231 ◽  
Author(s):  
Stephen J. Norton ◽  
Melvin Linzer
Keyword(s):  
Signal To Noise Ratio ◽  
Acoustic Pulse ◽  
Cutoff Frequency ◽  
Three Dimensional ◽  
Point Sources ◽  
Three Dimensions ◽  
Reconstruction Process ◽  
Dimensional Reconstruction ◽  
Reflectivity Data ◽  
Pulse Echo

Three-dimensional backprojection for reconstructing acoustic reflectivity within a volume is examined. The reflectivity data are acquired by means of a spherical array of point sources-receivers which encloses the object under study. Reconstruction of the image is obtained by back-projecting the recorded pulse-echo data over spherical surfaces in image space. An analytical expression for the point spread function (PSF) generated by the backprojection process has been derived. This expression was evaluated for several different choices of the acoustic pulse: a narrowband pulse, wideband pulse, and two analytically-derived optimum pulses which provide the best sidelobe response and a mainlobe width equal to approximately 0.4Λc, where Λc is the wavelength corresponding to the upper cutoff frequency of the pulse. Excellent agreement was obtained between the theoretical PSF's for the different pulses and those obtained by computer simulation. A number of potential advantages of direct three-dimensional reconstruction relative to two-dimensional tomographic techniques are discussed, including (1) high resolution in three dimensions (2) the possibility of incorporating refraction effects in the reconstruction process (3) reduced sensitivity to limited viewing anglesand (4) improved signal-to-noise ratio (thus minimizing requirements for data redundancy).

scholarly journals Research of the echo-impulse method of control of drilled pieces (non-destructive control)

2021 ◽  
Vol 350 ◽  
pp. 00013
Author(s):  
Dmitry Snezhkov ◽  
Neli Budrevich
Keyword(s):  
Propagation Velocity ◽  
Acoustic Pulse ◽  
Experimental Studies ◽  
Control Data ◽  
Shock Excitation ◽  
Impulse Method ◽  
Bored Piles ◽  
Pulse Echo ◽  
Non Destructive ◽  
Pulse Echo Method

The results of field and computational experimental studies of the pulse echo method are presented. Typical reflectograms of bored piles are presented. The factors that complicate the interpretation of control data are noted. An analysis of the formation of the fronts of an acoustic pulse during its shock excitation is presented. Estimates of the influence of reinforcement on the estimates of the propagation velocity of an acoustic pulse are given.

scholarly journals APPLICATION OF ACOUSTIC PULSE ECHO-METHOD FOR THE INVESTIGATION OF DYNAMIC AND STRUCTURAL DYSLOCATION CHARACTERISTICS OF CRYSTALS

2021 ◽  
pp. 142-148
Author(s):  
О.M. Petchenko ◽  
G.О. Petchenko ◽  
A.V. Bezugly ◽  
S.M. Boiko
Keyword(s):  
Plastic Strain ◽  
Acoustic Pulse ◽  
Strain Range ◽  
Mechanical Relaxation ◽  
Frequency Range ◽  
Dislocation Interaction ◽  
Plastic Strain Range ◽  
Elastic Loading ◽  
Pulse Echo ◽  
Pulse Echo Method

The multifunctional pulse equipment allowіng to use the method of amplitude-independent internal friction in the frequency range 7.5 to 232.5 MHz is described. Equipment gjves the possibility to investigate the peculiarities of the process of phonon-dislocation interaction in crystals, to carry out thermoactivation analysis of the process of dislocation of the dislocations about the stoppers under the action of temperature and elastic loading, to study processes of dislocation and mechanical relaxation in loaded samples in the quasi-elastic and plastic strain range.

scholarly journals Device for acoustic pulse echo experiments in the subterahertz range

2017 ◽  
Vol 95 (1) ◽  
Author(s):  
R. Legrand ◽  
A. Huynh ◽  
S. Vincent ◽  
B. Perrin ◽  
A. Lemaître
Keyword(s):  
Acoustic Pulse ◽  
Pulse Echo

Time-Resolved Thermal And Acoustic Pulse-Echo Measurements In Condensed Matter

1987 ◽  
Author(s):  
Gary L. Eesley ◽  
Carolyn A. Paddock ◽  
Bruce M. Clemens
Keyword(s):  
Condensed Matter ◽  
Acoustic Pulse ◽  
Time Resolved ◽  
Pulse Echo

Acoustic microscopy techniques for the inspection of integrated circuit devices and packages

1992 ◽  
Vol 50 (2) ◽  
pp. 966-967
Author(s):  
Thomas M. Moore
Keyword(s):  
Integrated Circuit ◽  
Acoustic Microscopy ◽  
Hybrid Technique ◽  
Frequency Scanning ◽  
Ic Packaging ◽  
Ic Package ◽  
Microscopy Techniques ◽  
Ic Package Inspection ◽  
Pulse Echo ◽  
Scanning Acoustic Microscope

In the last decade, a variety of characterization techniques based on acoustic phenomena have come into widespread use. Characteristics of matter waves such as their ability to penetrate optically opaque solids and produce image contrast based on acoustic impedance differences have made these techniques attractive to semiconductor and integrated circuit (IC) packaging researchers.These techniques can be divided into two groups. The first group includes techniques primarily applied to IC package inspection which take advantage of the ability of ultrasound to penetrate deeply and nondestructively through optically opaque solids. C-mode Acoustic Microscopy (C-AM) is a recently developed hybrid technique which combines the narrow-band pulse-echo piezotransducers of conventional C-scan recording with the precision scanning and sophisticated signal analysis capabilities normally associated with the high frequency Scanning Acoustic Microscope (SAM). A single piezotransducer is scanned over the sample and both transmits acoustic pulses into the sample and receives acoustic echo signals from the sample.

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