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Nuclear Safeguards Education Portal

Introduction to Gamma Ray Spectroscopy

U, Pu, and other nuclear materials all emit gamma ray radiation with a characteristic isotopic signature. There are a number of instruments used in detecting gamma ray radiation, including:

Of these, the scintillation and semiconductor detectors have the ability to provide energy resolution in addition to gross counts, though they tend to have lower efficiencies than gas-filled detectors.


What are the Advantages and Disadvantages of Gamma-Ray Spectroscopy?


  • detailed energy information available
  • instruments can be very portable
  • either isotopic composition (relative measurement) or grams of specific isotopes (absolute measurement) can be measured


  • gamma-ray absorption is significant (must be corrected for)
  • energy and efficiency calibrations are necessary
  • gamma measurements impractical if sample is large, dense, or heterogeneous


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