The analytical relationship that gives the neutron beam flux does
not take into account the probability of decay. In this research, we
concluded the analytical relationship of the probability non decay
of free neutron during the passage of the sam
ple to be analyzed by
NAA. And the conclusion of the analytical relationship to the
probability of non-capture of the free neutron during the its passage
of the sample to be analyzed by NAA in a simpler method than the
previous conclusion. We conducted an application study to
investigate the effect of the probability non decay of free
neutrons, that flowing through sample, On the flux of transient
neutron beam, for neutron beam with various large thickness
samples and for different energies of neutrons. The effect of
probability of neutron decay on neutron beam flux could not be
negligible for all the energies which are bigger than of
thermal.
