ABSTRACT
Objective To validate the effect of the Laboratory Sourceless Calibration Software (LabSOCS) in the actual sample measurement,and to study the effect of sample self-absorption correction and cascade radiation coincidence correction.Methods Two standard samples from the analytics company were measured using the two gamma spectrometers at our laboratory.The result were calculated using the efficiency generated by LabSOCS.Calculated result of each nuclide were analyzed.Results were compared with the standard value provided in the certificate.Results The LabSOCS may solve the problem of sample self-absorption correction in gamma energy spectrum measurement and analysis.The maximum deviation between the values of 241Am and 109Cd analyzed by LabSOCS and the reference value was less than 4％ for the broad-energy high-purity germanium gamma-ray spectrometers.However,the coincidence additive correction caused by cascade radiation could not be solved directly.Conclusions The research shows that the LabSOCS can solve the problem of sample self-absorption correction by describing the composition and density of the samples accurately.However,when analyzing the nuclides with cascade radiation,the coincidence addition effects should be considered.The flexible simulation method of the LabSOCS can be used to increase the distance from the cascade nuclide sample to the detector and to complete the accurate measurement of the cascade nuclide.
ABSTRACT
Objective To improve theγ-spectrometry analysis technology in water sample through the intercomparison conducted among the key laboratories. Methods To take part in the intercomparison of γ-spectrometry analysis in water sample organized by National Institute of Metrology ( NIM ) , the radionuclides of 238 U,226 Ra, 208 Tl, 228 Ac, 40 K, 241 Am, 137 Cs, and 60 Co in water sample were determined. The efficiency of the detector was calibrated renewedly by new standard source in 2015 and a new γ-spectrometry (BE5030) was used for sample measurement. Results Analysis and comparison of the three measurement results and the leading laboratory reference values showed that the results measured by γ-spectrometry ( BE5030 ) were better, especially for the natural radionuclides. The maximum En value between them and NIM reference value was only 0. 71. Conclusions The wide range energy γ-spectrometry (BE5030) has obvious advantages in the measurement and analysis of natural radionuclides. Due to the special structure of the wide range energy detector, its background interference is less in low energy area. This inter-comparison improved the accuracy of sample measurements and analysis, with good result achieved.
ABSTRACT
Objective To measure and analyze the radioactivity level of 210Pb in outdoor air in Beijing in spring.Methods Portable high flow air samplers were used to collect outdoor air at the ground level to analyze the 210Pb radioactivity in the aerosol filter samples using a laboratory-based high purity germanium (HPGe) γ spectrometer.Results The activity concentration of 210Pb outdoors ranged from 267.2 to 1 697.6 μBq/m3,with an average of (878.7 ± 386.7) μBq/m3.Statistical analysis showed that the activity concentrations 210Pb of outdoors varied with variable air quality.Conclusions The activity concentrations of 210Pb outdoors are detectable in Beijing,varying considerably but within the normal range.
ABSTRACT
Objective To improve theγ-spectrometry analysis technology in water sample through the intercomparison conducted among the key laboratories. Methods To take part in the intercomparison of γ-spectrometry analysis in water sample organized by National Institute of Metrology ( NIM ) , the radionuclides of 238 U,226 Ra, 208 Tl, 228 Ac, 40 K, 241 Am, 137 Cs, and 60 Co in water sample were determined. The efficiency of the detector was calibrated renewedly by new standard source in 2015 and a new γ-spectrometry (BE5030) was used for sample measurement. Results Analysis and comparison of the three measurement results and the leading laboratory reference values showed that the results measured by γ-spectrometry ( BE5030 ) were better, especially for the natural radionuclides. The maximum En value between them and NIM reference value was only 0. 71. Conclusions The wide range energy γ-spectrometry (BE5030) has obvious advantages in the measurement and analysis of natural radionuclides. Due to the special structure of the wide range energy detector, its background interference is less in low energy area. This inter-comparison improved the accuracy of sample measurements and analysis, with good result achieved.