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:

• gas-filled detectors
• scintillation detectors
• semiconductor detectors

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?

Advantages:

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

Disadvantages

• 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