Intercomparisons for the agreement of radioactivity measurement laboratories in environment

Four tests having for object the evaluation of ability of laboratories that solicit a ministerial agreement for the radioactivity measurement in environment are detailed: Water matrix, soil matrix, aerosol on filter matrix and biological matrix. For the first one test, water matrix, the categories of measures concerned are the gamma emitters radionuclides (gamma energy inferior to 100 keV), the level of activities is very low (sample: water). The second one, soil matrix, the categories of measures concerned are the uranium radioisotopes, thorium radioisotopes, radium 226 and daughter products, radium 228 and daughter products (sample: lake sediment). The third one test, aerosol on filter matrix, the categories of measures concerned are the global beta activity, the beta-gamma emitters radionuclides ( gamma energy superior to 100 keV, strontium 90 on yttrium 90 rate. For the fourth and last one test, on biological matrix the categories of measures concerned are the tritium and the strontium 90 on yttrium 90 rate (sample whole milk). The agreements are delivered by The I.R.S.N. ( Institute of radiation protection and nuclear safety). (N.C.)