Minimum target size in radiation force measurements

Beissner, K.

doi:10.1121/1.391433

Cited by 25 publications

(20 citation statements)

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“…In order to simplify the calculations, a lot of effort has been made [13]. Among them, Hasegawa [6] showed that the velocity potential at an observation point (r,θ ) in a focused field can be written as In expressions (7) and (8), j ( ) n x and (2) h ( ) n x are the spherical Bessel function and the spherical Hankel function of the second kind, P n (x) is the Legendre polynomial, and the time-dependent factor exp(jω t) is omitted. In spherical coordinates, the particle velocity can be read as…”

Section: Radiation Force On a Plane Absorbing Target In A Sphericallymentioning

confidence: 99%

“…Some corrections for finite size of the target should be made. Beissner [2] had suggested a minimum target size for plane piston sources. Therefore, when the acoustic power output from a transducer is determined through the radiation force measurements, it is crucial to establish a correct relationship between the radiation force and the corresponding acoustic power output for the radiated field of a practical transducer.…”

Section: Introductionmentioning

confidence: 99%

“…For a plane progressive wave, the force on a perfectly absorbing target can be denoted as F n =P/c, where F n is the radiation force along the normal direction of the target surface, and P and c are the acoustic power and sound speed, respectively. This is a simple relationship to link the radiation force and the acoustic power output from the transducer and is currently used as the basis of a great deal of practical work in ultrasonic dosimetry [1][2][3]. But in the determination of acoustic power by the radiation force method, the validity of the simple relationship F n =P/c is questionable for two reasons.…”

Section: Introductionmentioning

confidence: 99%

“…The expression (1) actually means that the intensity is uniform within the focused beam and becomes zero abruptly outside the focused beam. The relationship (2) has been used in many cases and is adopted as the national standard of China [5]. It is known that the steady force experienced by an object in a sound field is represented by closed integration of the radiation stress tensor along a surface enclosing the object.…”

Section: Introductionmentioning

confidence: 99%

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Radiation force on absorbing targets and power measurements of a high intensity focused ultrasound (HIFU) source

Zhang

Zhu

Ye³

et al. 2010

Sci. China Phys. Mech. Astron.

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Based on the analytic expressions for the radiated field of a circular concave piston given by Hasegawa et al., an integral for calculation of the radiation force on a plane absorbing target in a spherically focused field is derived. A general relation between acoustic power P and normal radiation force F n is obtained under the condition of kr 1. Numerical computation is carried out by using the symbolic computation program for practically focused sources and absorbing circular targets. The results show that, for a given source, there is a range of target positions where the radiation force is independent of the target's position under the assumption that the contribution of the acoustic field behind the target to the radiation force can be neglected. The experiments are carried out and confirm that there is a range of target positions where the measured radiation force is basically independent of the target's position even at high acoustic power (up to 700 W). It is believed that when the radiation force method is used to measure the acoustic power radiated from a focused source, the size of the target must be selected in such a way that no observable sound can be found in the region behind the target.Radiation force, targets, power measurements, high intensity focused ultrasound PACS: 43.25.Qr, 43.58.Pm, 43.80.Vj

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Section: Radiation Force On a Plane Absorbing Target In A Sphericallymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Radiation force on absorbing targets and power measurements of a high intensity focused ultrasound (HIFU) source

Zhang

Zhu

Ye³

et al. 2010

Sci. China Phys. Mech. Astron.

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“…10,11 The technique recommended in IEC 61161 uses a radiation force balance (RFB). 6 An appropriately constructed target, properly aligned in a steady state under ultrasound field, is subjected to a radiation force given by [12][13][14] …”

Section: Introductionmentioning

confidence: 99%

Measurement of total ultrasonic power using thermal expansion and change in buoyancy of an absorbing target

Dubey

Kumar

Gupta

et al. 2014

Review of Scientific Instruments

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A compact and miniaturized high resolution capacitance dilatometer for measuring thermal expansion and magnetostriction Rev. Sci. Instrum. 83, 095102 (2012) The Radiation Force Balance (RFB) technique is well established and most widely used for the measurement of total ultrasonic power radiated by ultrasonic transducer. The technique is used as a primary standard for calibration of ultrasonic transducers with relatively fair uncertainty in the low power (below 1 W) regime. In this technique, uncertainty comparatively increases in the range of few watts wherein the effects such as thermal heating of the target, cavitations, and acoustic streaming dominate. In addition, error in the measurement of ultrasonic power is also caused due to movement of absorber at relatively high radiated force which occurs at high power level. In this article a new technique is proposed which does not measure the balance output during transducer energized state as done in RFB. It utilizes the change in buoyancy of the absorbing target due to local thermal heating. The linear thermal expansion of the target changes the apparent mass in water due to buoyancy change. This forms the basis for the measurement of ultrasonic power particularly in watts range. The proposed method comparatively reduces uncertainty caused by various ultrasonic effects that occur at high power such as overshoot due to momentum of target at higher radiated force. The functionality of the technique has been tested and compared with the existing internationally recommended RFB technique. © 2014 AIP Publishing LLC. [http://dx

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Ultrasonic Power Balances

Davidson¹

1991

Output Measurements for Medical Ultrasound

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Minimum target size in radiation force measurements

Cited by 25 publications

References 0 publications

Radiation force on absorbing targets and power measurements of a high intensity focused ultrasound (HIFU) source

Radiation force on absorbing targets and power measurements of a high intensity focused ultrasound (HIFU) source

Measurement of total ultrasonic power using thermal expansion and change in buoyancy of an absorbing target

Ultrasonic Power Balances

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