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Re: Physical particle size to AMAD
I do not think there is a safe way to derive the AMAD from electron
microscope images. The AMAD is what it says it is: the ''AERODYNAMIC MEDIAN
ACTIVITY diameter''. You would have to know first if the particle measured
with the electron microscope is radioactive. Then, the aerodynamic diameter
is the diameter of a sphere of density one with the same settling velocity
or mean Brownian motion velocity than the particle in your cloud of
particles. Density and shape factors have a strong influence on the AMAD.
Further, in order to determine the M of the AMAD, you need to know the size
distribution of the particles of interest and to determine the median of the
distribution. From electron microscope images, you can only determine the
median of the distribution. You would have to use diffusion batteries of
the appropriate type for the size range of interest and radiation counting
to determine the AMAD.
Philippe Duport
----- Original Message -----
From: "Michael Ford" <MFORD@PANTEX.COM>
To: <radsafe@list.vanderbilt.edu>
Sent: Thursday, June 14, 2001 11:22 AM
Subject: Physical particle size to AMAD
> Dear colleagues,
>
> I am looking for a published reference describing the methodology for
converting a physical particle diameter - as determined via a scanning
electron microscope - to an activity median aerodynamic diameter (AMAD).
>
> If you have any information, please reply directly to me. I receive
RADSAFE messages in digest mode and was hoping to get some feedback before
the end of the day.
>
> Thanks very much in advance for your help!
> v/r
> Michael
> mford@pantex.com
>
>
>
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