The following report summarizes the results obtained in the May, 2007 sample distribution for the Tritium Intercomparison Program, which is administered by the National Calibration Reference Centre for Bioassay, Radiation Protection Bureau.
Samples were prepared as described in previous reports [1,2]. The spike levels tested were:
(1) 5.01 x 103 Bq/L
(2) 1.50 x 105 Bq/L
(3) 1.00 x 106 Bq/L
and the date of spiking was April 2, 2007. Each laboratory was provided with five aliquots of each spike and of the corresponding urine matrix from which each spiked sample had been prepared. In this intercomparison, the matrix for Spike 3 was colour-quenched to reduce its counting efficiency to approximately 66% of the original value.
Instructions for sample analysis and the reporting of results were enclosed with the samples.