The material was obtained from a processing plant located in Gdansk (Poland) in 2003. The material was dried and milled by air jet mill to less than 100 μm, and homogenized. Bottling of IAEA-434 was carried out under normal laboratory conditions. Portions of 250 g each were filled into plastic bottles, sealed with security polyethylene caps and labelled with the code IAEA-434. After bottling the material was sterilized by gamma ray irradiation with a total dose of 25 kGy using a Co-60 source to ensure long-term stability of the material by inhibiting microbial action.
Reference date for decay correction: 2008-01-01
| Analyte | Certified value [Bq kg-1] | Uncertainty* [Bq Kg-1] |
| 210Pb | 680 | 58 |
| 226Ra | 780 | 62 |
| 230Th | 211 | 9 |
| 234U | 120 | 9 |
| 238U | 120 | 11 |
* Uncertainty is expressed as a Mixture model median based standard deviation S(MM-median) at 95 % confidence level.
Four National Metrological Institutes (NMI) and seven expert laboratories nominated by their respective NMI took part in the IAEA-434 interlaboratory comparison; namely: ERISS (Australia), PTB (Germany), HAA (Hungary), ARPA (Italy), KINS (Korea), KRISS (Korea), LNHB (France), MNA (Malaysia), IJS (Slovenia), AECS (Syria), and the IAEA Laboratories (Austria).
The property values of all radionuclides were established on the basis of the Mixture Model Median (MM-median) of the analytical results reported by the expert laboratories.
To estimate the standard uncertainty associated with the property value the MM-median based Standard Deviation S(MM-median) was calculated from the span of the central 50% of the MM-PDF density function.
