• Always select a high intensity gamma peak at the high energy end of the spectrum. At this energy there is less ambiguity and so peaks can be identified easier than from lower energies.
  
• Consult a table of isotopes so that identification can be performed.
  
• The isotope associated with an energy can be confirmed by checking the associated gamma energies with that isotope and seeing if that peak is found in the spectrum.
  
• Now repeat the above by selecting the next intense unidentified gamma ray and continue until all possible peaks are identified.

Click here to for an exercise in nuclide source and energy identification.