Kerma - definition

[aenns@unixg.ubc.ca (Alan Enns)]

Ken:

Kerma is a term used in the case of indirectly ionizing radiation (ie x-rays 
and fast neutrons).  Essentially, it is the initial kinetic energy of the 
primary ionizing particles (photoelectrons, Compton electrons, and 
posi/negatron pairs from photon radiation, and scattered nuclei from fast 
neuts.) produced by the interaction of the incident radiation per unit mass 
of interacting medium.  The units are J/kg (Gray) or rads to you 
Southerners.  The kerma decreases continuously with increasing depth in the 
absorbing material because the flux of the indirectly ionizing radiation 
also decreases continuously.

hope this helps...

>Now that we know about mass energy absorption coefficients,
>what is kerma??
>
>Ken
>
>
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Alan Enns
Radiation Safety Assistant,
Department of Health, Safety and Environment
University of British Columbia,
Canada.
aenns@unixg.ubc.ca
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