THE EGS5 CODE SYSTEM

W = Atomic, molecular and mixture weight for an element, for a compound, and for a mixture.
In EGS, K-shell vacancy creation by EII is sampled using R(E, J) values calculated in PEGS
and included in the material data file.
K-x ray emission and energy deposition After K-shell vacancy creation by EII, emission of K-
x rays is sampled using the K-shell fluorescence yield [57], as in the treatment of the photoelectric
effect [73]. However, in the current EGS implementation, neither Auger electron emission nor
atomic relaxation cascades are modeled for K-shell vacancies generated by EII. K-shell x-ray energies
are sampled from the ten possible lines given in [57], and the difference between the K-shell binding
energy E B and the emitted x-ray energy is deposited locally. In the case when no x-ray is generated
(i.e., an Auger electron emission occurred), the full binding energy E B is deposited locally.
Secondary electron energies and angles The energy and direction of ejected electrons following
EII are treated in an approximate manner. The binding energy E B is subtracted at random
from the energy of either one of the two electrons after energies have been determined from the
standard Møller scattering analysis. In the case that neither of the two electron has kinetic energy
greater than E B , E B is subtracted from the energy of both electrons while keeping the ratio of the
kinetic energies unchanged. The directions of electrons after EII are those given from the Møller
scattering collision analysis.
139