Comparison of two techniques for low-level tritium measurement – gas proportional and liquid scintillation counting (CROSBI ID 564301)
Prilog sa skupa u zborniku | sažetak izlaganja sa skupa
Podaci o odgovornosti
Barešić, Jadranka ; Horvatinčić, Nada ; Krajcar Bronić, Ines ; Obelić, Bogomil
engleski
Comparison of two techniques for low-level tritium measurement – gas proportional and liquid scintillation counting
Measurement of low-level tritium activities in natural/no polluted waters, e.g. in precipitation and groundwaters, requires special techniques for water pretreatment and detection of low-level radioactivity. Two methods for low-level tritium measurement have been developed in Zagreb Radiocarbon and Tritium Laboratory: gas proportional counting (GPC) and liquid scintillation counting (LSC). GPC technique has been used since 1978. CH4 is obtained by reaction of water (50 ml) with aluminium carbide at 150°C, purified and used as a counting gas in a multi-wire GPC. The counting energy window is set to energies between 1 keV and 10 keV to obtain the best figure of merit. Gas quality control has been performed by simultaneous monitoring of the count rate above the tritium channel, i.e., above 20 keV. The limit of detection is 3 TU. New method of tritium measurement by LSC Quantulus 1220 using electrolytic enrichment of water samples has been developed in 2008. System of electrolytic enrichment consists of 20 cells of 500 ml volume and equipments for primary and secondary distillations. For each enrichment run 3 spike and 2 dead-water samples are used for system control. Final volume of water sample after electrolysis is 19±1 ml and obtained enrichment factor is 20±2. Mixture of 8 ml of water and 12 ml of scintillation cocktail Ultima Gold in plastic vial is used for counting in LSC. The limit of detection is 0.3 to 0.5 TU. Our Laboratory participated in the intercomparison study organized by the IAEA, TRIT2008. The data evaluation of six samples using S-plot analyses revealed that all results measured by LSC are accepted, and for GPC results four results are accepted and two results of samples with low tritium activity (<2 TU) are in the warning level. The tritium results of TRIT2008 intercomparison as well as of groundwater and precipitation samples will be presented for both GPC and LCS techniques.
tritium; measurement techniques; GPC; LSC; enrichment
nije evidentirano
nije evidentirano
nije evidentirano
nije evidentirano
nije evidentirano
nije evidentirano
Podaci o prilogu
212-212.
2010.
objavljeno
Podaci o matičnoj publikaciji
Abstracts. Third European IRPA Congress: Radiation protection - science, safety and security
Helsinki: International Radiation Protection Association (IRPA)
978-952-478-549-5
Podaci o skupu
Third European IRPA Congress: Radiation protection - science, safety and security
poster
14.06.2010-18.06.2010
Helsinki, Finska