Template measurement is of importance in deep nuclear disarmament.The γ-ray spectrum of plutonium pit shows unique property due to age

isotopic abundance and mass of the plutonium pit.The pits of the same design have similar γ-ray spectra

but the spectrum differs form that of a pit in different design.Useful information can be extracted from γ-ray spectrum generated by using a standard plutonium pit as a template.A comparison between the inspected objects and the template leads to conclusion whether they are of the same type.In this paper

we study how to choose the template data from γ-ray spectrum and discuss limitations of using the γ-ray spectrum only.Because of strong self-absorption of plutonium

some characteristics of plutonium pit cannot be identified by the gamma spectrum only.MCNP simulations were employed to prove that

in some cases

template depending on just the γ-ray spectrum cannot effectively distinguish the spurious objects.And a further approach indicates that enhancing neutron counting rate of spontaneous fission of plutonium can improve the model identification.