ABSTRACT
Information about how the laboratory of Centro de Protección e Higiene de las Radiaciones (CPHR), Cuba establishes its traceability to the International System of Units for the measurement of radionuclides in environmental test items is presented. A comparison among different methodologies of uncertainty calculation, including an analysis of the feasibility of using the Kragten-spreadsheet approach, is shown. In the specific case of the gamma spectrometric assay, the influence of each parameter, and the identification of the major contributor, in the relative difference between the methods of uncertainty calculation (Kragten and partial derivative) is described. The reliability of the uncertainty calculation results reported by the commercial software Gamma 2000 from Silena is analyzed.
Subject(s)
Algorithms , Data Interpretation, Statistical , Environmental Exposure/analysis , Radiation Monitoring/methods , Radiation Monitoring/standards , Radioisotopes/analysis , Radioisotopes/standards , Cuba , Radiation Dosage , Reference Standards , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
To study the influence of the source's chemical composition on the self-attenuation corrections during the activity quantification of low-energy gamma-ray emitters (< 60keV) in soil samples, we conducted a Monte Carlo-based hypothetical proficiency test in which different analytical laboratories analyze a soil sample, assuming the same density but a different chemical composition. The bias in the activity values was between 4% and 70%, with more than 50% of these results being unacceptable. Our work shows that collecting the detailed chemical composition of the samples is an essential issue to be considered by analytical laboratories that use the Monte Carlo method for the calculation of self-attenuation corrections.