6.5 Safety Issues
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To this aim, NCRP considered a list of thermal and fast neutron activation
products of elements with atomic number between 1 and 60, plus gold, plati-
num, iridium, and bismuth, high-Z elements that occur in pharmaceuticals
and medical devices. For the fast neutron activation, a narrow energy distribu-
tion, with a peak at 8.5 MeV and a total uence of 6.4 × 10
5
n/cm
2
was assumed.
is is the specied neutron uence at the surface of a container scanned by
the PFNA system. is approximation neglects the decrease of the total u-
ence with neutron beam penetration inside the container as well as the lower
energy neutrons generated by scattering. However, the structure of the fast
neutron activation cross sections that produce ...