Most radionuclides decay by gamma ray emission. Gamma ray measurement is the most common and widely used method for measuring nuclear material. It can be used to determine three different qualities of a sample:
- Total dose rate (commonly used for medical purposes)
- Ratio of the constituents of the sample
- Total radionuclide content of a source, either in terms of activity of the mass of a particular radionuclide
The gamma ray measurement process can be passive or active. In PASSIVE measurement the gamma rays emitted form radioactive decay are measured by appropriate detectors and counting electronics. In ACTIVE measurement gamma rays are used to interrogate samples and the attenuation of these interrogating gamma rays is measured. This is used to determine the ability for transmission through samples and thus the degree of attenuation in the sample material and the matrix in which it is contained.
ANTECH instruments perform gross gamma counting using ion chambers and plastic scintillators, and spectroscopy using low-resolution spectrometers (sodium iodide scintillators) or medium and high-resolution spectrometers (LaBr3scintillators and high purity germanium detectors). ANTECH instruments are configured to perform far field measurements to view entire objects, and segmented and tomographic gamma scanning for more complex samples.