A preliminary intercomparison of gamma-ray spectrometry on building materials

A preliminary intercomparison on gamma-ray spectrometry determination of natural radionuclides in building materials was carried out in 1999-2002. Samples measured were fly ash, sand and tuff. Laboratories used different experimental equipment and procedures. Corrections for blank, spectral interference, self-absorption and coincidence summing effects were applied in most cases. The agreement between results was within 15-20%, most often within the reported uncertainties. Several general conclusions can be drawn regarding procedures correctness, uncertainty budget, secular equilibrium condition, and radionuclide representativeness in each natural series. Further studies are needed to draw more specific conclusions.