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radionuclies. Besides that, Improvement in the mea-
surement of short live radionuclie can be obtained via
minimizing the interference of long live radionuclie by
reducing the irradiation time. In this case, the resolu-
tion of the measurement system should be sufficient.
This flexiblity of NAA is a key advantageous of other
analytical techniques.

In many cases, the β particle is also emitted to-
gether with γ-ray during radioisotopic decay. The qual-
itative parameters from measurement is energy of the
emitted gamma ray and the half-live of radioactive nu-
clies. While, the quantitative parameters is the γ inten-
sity which reflects the total number of quanta γ energy
perunit time.

As mentioned ealier, NAA is resulted from (n,γ) nu-

clear reaction, Following is the example for this reac-

tion of iron isotope; 197Au + 1n 198Au + β– + γ ray.

Where, 198Au is a radioactive isotope resulting from

nuclear reaction of stable isotope 197Au with neutron.

The gamma ray emmited during the decay of 198Au nu-

cleus have energies of 1087.7 keV and 411.8 keV. De-
cay scheme of 198Au due to neutron-capture nuclear

reaction is given in Figure 3.2. The interaction of neu-

tron with the nucleus of atom is a probability process

as a function of neutron energy. The probability pro-

cess is referred to the capture cross-section of nucleus

atom. Hence, each nuclide has neutron capture cross-

section with neutron energy relationship.

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