Calculate the amplitude of the pulse that is reflected from a disc-shaped reflector

[mikewill54]

Hi
Hoping someone can help me with this question, Im a bit stumped but I think im on the right track

Calculate the amplitude of the echo that is reflected from a disc-shaped reflector with a diameter of 0.7 mm at a depth of 60 mm, as a fraction of the transmitted pulse.

wave velocity is 5.96 mm/μs,
attenuation coefficient is 0.05 nepers/mm.
A compression probe - 10 mm diameter and 4 MHz frequency
attenuation coefficient is 0.05 nepers/mm
required amplification of the back wall echo to inspect the stainless steel block is observed to be 20 dB.

I think I'm supposed to use this formula from
Ermolovs Sizing equations

[math]p=(SAe^(-2αT))/(T^2 λ^2 )[/math]

T = the distance along the beam axis to the target

S = the area of the probe

lambda = the wavelength of ultrasound (nominal)

alpha = the attenuation coefficient

A = Area of flat shaped reflector



T = 50

S = 78.53

lambda = 0.00149

alpha = 0.05

A = 0.38


Does anyone know if this is close to being right, I cant find much online about it
Thanks for any help