CPB Ljubljana 2018 course book

Particles – Effective Energy

Example:  - decay of 137 Cs  Photons

For dosimetric purposes it is more appropriate to consider the effective energy E eff defined as the air-kerma weighted mean energy. This is given by:

  

  





2

tr



Ef i



i





E ,

i

i

E





651.8keV

eff

tr       

  



Ef

i

i

Characteristic  -rays



E ,

i

i

is the mass energy transfer coefficient for photons of energy E i in air. i E ,α tr ρ μ      

f

E

i

i