The average cross- section for fast neutron reactions with the elements (Mg , Al, Fe,
Ni, Zn , Cu) in 65 Cu(n, p) 65 Ni, 64 Zn(n, p) 64 Cu, 58 Ni(n, p) 58 Co, 56 Fe(n, p) 56 Mn, 57 Al(n,
p) 57 Mg and 24 Mg(n, p) 24 Na reactions has been calculated by using the numerical –
graphical method for 241 Am/Be neutron source according to the intensity distribution
of the source as a function of neutron energy. The corresponding neutron cross-
section values at certain energies are taken from neutron cross-sections curves.
Furthermore, the average neutron cross-sections for each of these reactions have been
measured using the activation method. A well-type NaI(Tℓ) detector was used for
measuring the radiation activity.
The cross-sections for these reaction were measured by using of 27 Al(n, p) 27 Mg
reaction as a reference for short-lived activity arising in the different reactions. For
long - lived activities the 27 Al(n, ) 24 Na, and 56 Fe (n, p) 56 Mn are used. It is found that
the cross – section for the 65 Cu isotope is σ =826.29±62 mb while the standard value
is σ =962±60 mb for the same.We have found the relative neutron activation method
is more accurate than the absolute neutron activation method to stabilize the value of
neutron flux through the use of the monitor reaction.