1. Laboratories receive well-characterised samples, with certified amounts of the measured isotopes but with undisclosed values. The certified values, established as far as possible at IRMM, are disclosed to laboratories upon receiving their results.
2. Participating laboratories are asked to perform the measurements working under routine conditions using the techniques, procedures and instrumentation of their own choice.
3. Participating laboratories should supply a best estimate of the expanded measurement uncertainty on their results.
4. Individual measurement results of participants are compared against the certified reference value provided by IRMM. The certified reference value has a demonstrated uncertainty evaluated according to international guidelines and demonstrates traceability to the SI.
5. Programmes are focused as much as possible on real-life samples.
6. Campaigns are open to all interested laboratories.
7. The names of the participating laboratories may be published. However the measured results are not linked to the names of the laboratories, thus ensuring the participants’ confidentiality.
8. For most of the campaigns an administrative charge is made. In exceptional circumstances payment of the charges may be waived.