Materials are investigated for coupling ultrasound between solid piezoelectric transducers and solid targets having acoustic impedances ranging between 10–20 MRayl. The majority of available acoustic couplants have impedances below 5 MRayl, leading to large surface reflections and acoustic losses. The desired couplant is preferably liquid or semiliquid with good conformability and low attenuation. This study examines the acoustic properties of various couplants, including gallium–indium alloys. Transmission tests were conducted at 19 MHz, concluding that these alloys are most appropriate for the stated application, with low attenuation, high acoustic impedance (17.4 MRayl), and a measured compressional velocity of 2740 m/s.
REFERENCES
1.
J. Szilard, Ultrasonic Testing Non-conventional Testing Techniques (Wiley, Chinchester, UK, 1982), Chap. 9.
2.
M. O.
Culjat
, R. S.
Singh
, E. R.
Brown
, R. R.
Neurgaonkar
, D. C.
Yoon
, and S. N.
White
, “Ultrasonic crack detection in a simulated human tooth
,” Dentomaxillofac Radiol.
34
, 80
–85
, (2005
).3.
Acoustic Material Table (Onda Corporation, Sunnyvale, CA, 2004); 〈http://www.ondacorp.com〉.
4.
S.
Lees
and F. E.
Barber
, “Looking into teeth with ultrasound
,” Science
161
, 477
–478
(1968
).5.
M.
Culjat
, R. S.
Singh
, D. C.
Yoon
, and E. R.
Brown
, “Imaging of human tooth enamel using ultrasound
,” IEEE Trans. Med. Imaging
22
(4
), 526
–529
(2003
).6.
L. E. Kinsler, A. R. Frey, A. B. Coppens, and J. V. Sanders, Fundamentals of Acoustics, 4th ed. (Wiley, New York, 2000), Chap. 6.
7.
S.
Chaffai
, F.
Padilla
, G.
Berger
, and P.
Laugier
, “In vitro measurement of the frequency-dependent attenuation in cancellous bone between 0.2 and 2 MHz
,” J. Acoust. Soc. Am.
108
(3
), 1281
–1289
(2000
).8.
S. Ng, P. Payne, and M. Ferguson, “Ultrasonic imaging of experimentally induced tooth decay,” International Conference on Acoustic Sensing and Imaging, 82–86 (London, UK, 29–30 March, 1993).
9.
S. R.
Ghorayeb
and T.
Valle
, “Experimental evaluation of human teeth using noninvasive ultrasound: Echodentography
,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control
49
(10
), 1437
–1443
(2002
).10.
C.
Louwerse
, M.
Kjaeldgaard
, and M. C. D. N. J. M.
Huysmans
, “The reproducibility of ultrasonic enamel thickness measurements: An in vitro study
,” J. Dent.
32
, 83
–89
(2004
).11.
L. E. Kinsler, A. R. Frey, A. B. Coppens, and J. V. Sanders, Fundamentals of Acoustics, 4th ed. (Wiley, New York, 2000), Chap. 8.
12.
E. A. Ginzel and R. K. Ginzel, “Ultrasonic properties of a new low attenuation dry couplant elastomer,” NDTnet, 1(2) (1996); 〈http://www.ndt.net/article/ginzel/ginzel.htm〉.
13.
G. S. Kino, Acoustic Waves: Devices, Imaging, and Analog Signal Processing (Prentice-Hall, Englewood Cliffs, NJ, 1987), Chap. 3.
14.
S. Eckert, G. Gerbeth, V. I. Melnikou, C. H. Lefhalm, and J. Knebel “Application of ultrasound Doppler velocimetry to flows of hot metallic melts,” Third International Symposium on Ultrasonic Doppler Methods for Fluid Mechanics and Fluid Engineering, EPFL (Lausanne, Switzerland, September 2002), 77–82; 〈http://lchwww.epfl.ch〉.
15.
V. B.
Jipson
, “Acoustic microscopy of interior planes
,” Appl. Phys. Lett.
35
(5
), 385
–387
(1979
).16.
H.
Wang
, T.
Ritter
, W.
Cao
, and K. K.
Shung
, “High frequency properties of passive materials for ultrasonic transducers
,” IEEE Trans. Ultrason. Ferroelectr. Freq. Control
48
(1
), 78
–83
(2001
).17.
J. N.
Koster
, “Directional solidification and melting of eutectic GaIn
,” Cryst. Res. Technol.
34
(9
), 1129
–1140
(1999
).18.
Specialty Alloys (AIM Solder, Cranston, RI, 2005); 〈http://www.aimsolder.com〉.
19.
J. Rancourt and L. T. Taylor, “Metallic material with low melting temperature,” United States Patent Number 5508003 (1996).
20.
D.
Brito
, H. C.
Nataf
, P.
Cardin
, J.
Aubert
, and J. P.
Masson
“Ultrasonic Doppler velocimetry in liquid gallium
,” Exp. Fluids
31
, 653
–663
(2001
).21.
S. L.
Hulbert
, “Interaction of InGa liquid alloy coolant with gold-coated optical materials
,” Rev. Sci. Instrum.
63
(1
), 505
–508
(1992
).22.
J. E.
Chandler
, H. H.
Messer
, and G.
Ellender
, “Cytotoxicity of gallium and indium ions compared with mercuric ion
,” J. Dent. Res.
73
, 1554
–1559
(1994
).23.
D.
McComb
, “Gallium restorative materials
,” J. Can. Dent. Assoc.
64
, 645
–647
(1998
).24.
D. F.
Baldwin
, R. D.
Deshmukh
, and C. S.
Hau
, “Gallium alloy interconnects for flip-chip assembly applications
,” IEEE Trans. Compon. Packag. Technol.
23
(2
), 360
–366
(2000
).25.
R. S. Singh, “Design, fabrication, and characterization of an ultrasonic crack detection system for human teeth,” Ph.D. dissertation (University of California, Los Angeles, 2005).
26.
Ultra/Phonic (Pharmaceutical Innovations, Inc., Newark, NJ, 2005); 〈http://www.pharminnovations.com/〉.
27.
HighZ Couplant (Sonotech, Inc., Bellingham, WA, 2005); 〈http://www.sonotech-inc.com/〉.
This content is only available via PDF.
© 2005 Acoustical Society of America.
2005
Acoustical Society of America