Mass Energy Absorption Coefficient -Reply

[SIMPSOND@ORAU.GOV]

The ICRU has defined the mass energy absorption coefficient in ICRU 33.
 Its definition:  the product of the mass energy transfer coefficient and
(1-g) where g is the fraction of energy of secondary charged particles
that is lost to bremsstahlung.  

Earlier in ICRU the mass energy transfer coefficient is defined as  the
fraction of incident particle energy that is transferred to kinetic energy of
charged particles by interactions, in traversing a distance of material.

(Note: I have shortened both of these definitions so if you need the exact
form refer to ICRU 33)

In summary  the mass energy absorption coefficient represents the
energy absorbed as the result of radiation interactions, but does not
include the energy that is radiated away and deposited elsewhere.

Dave Simpson   ORAU