Primary measurement of ultrasonic power and dissemination of ultrasonic power reference values by means of standard transducers

Beissner, K.

doi:10.1088/0026-1394/36/4/10

Cited by 34 publications

(19 citation statements)

References 6 publications

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“…Indeed, few absolute measurements obtained independently in the same experiment of the acoustic power generated by an acoustic source and the radiation force incident on a target to assess the radiation pressure-energy density relationship have been reported. Typically, experimental assessments of the radiation pressure have either relied on the assumption of the Langevin relation a priori in evaluating the transducer power output [18][19][20][21][22] or have considered relative measurements without directly evaluating the transducer power output (cf, [8,9,38,39]). Beissner [21] points out that if acoustic radiation pressure is used to calibrate acoustic sources the 'measured radiation force must be converted to the ultrasonic power value and this is carried out with the help of theory.'…”

Section: Experimental Evidence For the Present Theorymentioning

confidence: 99%

Acoustic radiation pressure in laterally unconfined plane wave beams

Cantrell

2019

J. Phys. Commun.

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The acoustic radiation pressure in laterally unconfined, plane wave beams in inviscid fluids is derived via the direct application of finite deformation theory for which an analytical accounting is made ab initio that the radiation pressure is established under static, laterally unconstrained conditions, while the acoustic wave that generates the radiation pressure propagates under dynamic (sinusoidal), laterally constrained conditions. The derivation reveals that the acoustic radiation pressure for laterally unconfined, plane waves along the propagation direction is equal to (3/4)〈2K〉, where á ñ K is the mean kinetic energy density of the wave, and zero in directions normal to the propagation direction. The results hold for both Lagrangian and Eulerian coordinates. The value á ñ ( ) / K 3 4 2 differs from the value á ñ K 2 ,traditionally used in the assessment of acoustic radiation pressure, obtained from the Langevin theory or from the momentum flux density in the Brillouin stress tensor. Errors in traditional derivations leading to the Brillouin stress tensor and the Langevin radiation pressure are pointed out and a long-standing misunderstanding of the relationship between Lagrangian and Eulerian quantities is corrected. The present theory predicts a power output from the transducer that is 4/3 times larger than that predicted from the Langevin theory. Tentative evidence for the validity of the present theory is provided from measurements previously reported in the literature, revealing the need for more accurate and precise measurements for experimental confirmation of the present theory.wave. This result differs considerably from the value á ñ K 2 for the radiation pressure obtained from the Langevin theory [29] or from the Brillouin stress tensor [26,27]. In the directions normal to the propagation direction, the radiation pressure is zero for both Lagrangian and Eulerian coordinates.The difference between the present assessment of radiation pressure and that obtained from the Langevin theory or from the Brillouin stress tensor is significant, since the assessment is used to link the radiation force on a target with the power generated by acoustic sources. As pointed out by Beissner [21], the 'measured radiation force must be converted to the ultrasonic power value and this is carried out with the help of theory.' It is generally assumed that for laterally unconfined, plane wave beams the relationship between the acoustic radiation pressure and the energy density for plane waves in the direction of wave propagation is that obtained from the Langevin theory [29] or from the Brillouin stress tensor [26,27]. The present model predicts a transducer output power 4/3 times larger than that predicted from the Langevin theory or from the Brillouin stress tensor. This has considerable implications regarding safety issues for medical transducers, calibrated using radiation pressure.Issenmann et al [52] point out that 'despite the long-lasting theoretical controversies K the Langevin radiation pressure K has been the...

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Section: Experimental Evidence For the Present Theorymentioning

confidence: 99%

Acoustic radiation pressure in laterally unconfined plane wave beams

Cantrell

2019

J. Phys. Commun.

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“…The accepted technique for determining ultrasound output power is by measurement of radiation force, and a substantial body of literature exists which details the concept, theory and practical implementation [29][30][31][32][33][34][35]; a range of commercially-available devices for this purpose are available. As such, the basic concepts of the method will be considered only briefly here.…”

Section: Ultrasonic Power -Radiation Forcementioning

confidence: 99%

Calibration and measurement issues for therapeutic ultrasound

Shaw

Hodnett

2008

Ultrasonics

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“…Figure 10 illustrates key features of the arrangement used: the target is hanging under the balance, the water tank is not in contact with the balance pan and the transducer is radiating upwards through a hole in the bottom of the water tank (Beissner 1999). The nominal power values used in the calibration were 100 mW, 500 mW, 3 W and 15 W for the "large" transducers (A ER Ͼ 100 mm 2 ) and 100 mW, 300 mW, 1 W and 3 W for the "small" transducers (A ER Ͻ 100 mm 2 ).…”

Section: Fundamental Power Measurementmentioning

confidence: 99%