Attenuation coefficient of water

[lavster]

I have read that the attenuation of water (for ultrasound) is 0.0472 Np m–1
(MHz)–2.

What is this in dB/cm/MHz^-2 ? What is Np?

thanks

 

[davenn]

Np = Neper, its another way of describing attenuation loss

see this wiki for a longer explanation
http://en.wikipedia.org/wiki/Neper

there's sure to be converters on the net to do the conversion between Neper and dB
Google is your friend :)

Dave

 

[lavster]

thanks :)