Analysis of radionuclides at ultra-low levels: A comparison of low and high-energy mass spectrometry with gamma-spectrometry for radiopurity measurements.

Recent developments in high-energy accelerator mass spectrometry (AMS) and low-energy inductively coupled plasma mass spectrometry (ICPMS) made them the most sensitive techniques for ultra low-level analysis of 238U and 232Th. Detection limits below 1 nBq g-1 for analysis of these radionuclides in construction materials were obtained. The most important development in the radiometric sector was operation of HPGe detectors in underground laboratories where detection limits of about 1 µBq kg-1 were obtained. Specific features of radiometric, mass spectrometry and neutron activation techniques for ultra low-level radionuclide measurements are discussed, and obtained results for analysis of radiopure materials prepared for underground experiments are compared.