Application of analytical methods based on X-ray spectroscopy to the determination of radionuclides

Low levels of radionuclides are commonly determined by radiometric counting methods. However, for long lived radionuclides and for those nuclides with low energy emissions, such as soft beta emitters, non-radiometric methods can offer a more sensitive alternative. This work investigates the use of various analytical methods based on x-ray spectroscopy for the determination of low levels of radionuclides. X-ray spectroscopy cannot provide the isotopic information available from many radiometric or mass spectrometric methods but this is not always required when the radioisotope of interest is the major isotope, as could be the case with 238U or 99Tc, for example. X-ray fluorescence, total reflectance x-ray fluorescence, electron microprobe analysis, particle-induced x-ray emission and synchroton radiation-induced x-ray emission are considered in a practical intercomparison of methods. X-ray methods are relatively insensitive compared with mass spectrometric techniques but are suitable for the determination of long-lived nuclides such as 232Th and 238U.