RESUMO
In 2010, a comparison of activity measurements of (99m)Tc was carried out at the KRISS using the BIPM's Transfer Instrument of the International Reference System (SIRTI). The transfer instrument and the KRISS coincidence measurement method are briefly described. The degrees of equivalence with the key comparison reference value and between the present KRISS result and the earlier participants in the SIRTI and SIR comparisons have been evaluated. World-wide consistency of activity measurements of (99m)Tc is demonstrated.
Assuntos
Radiometria/instrumentação , Radiometria/normas , Tecnécio/análise , Tecnécio/química , Doses de Radiação , Padrões de Referência , Valores de Referência , República da Coreia , Tecnécio/normasRESUMO
Alpha-emitting 238Pu and 241Am sources on stainless steel substrates have been prepared using a new electrodeposition method based on an ammonium oxalate-ammonium sulfate electrolyte containing diethyl triamino pentaacetic acid. The deposition yield is determined by measuring the activity of the sources using a high-efficiency 2pi alpha proportional counter and a backscattering chamber designed and fabricated for this purpose. Optimal electrodeposition parameters have been determined for 241Am, enabling manufacture of standard alpha-emitting sources with minimal radioactive waste.
Assuntos
Partículas alfa , Galvanoplastia/métodos , Galvanoplastia/normas , Monitoramento de Radiação/normas , Padrões de Referência , Valores de Referência , Amerício/análise , Amerício/química , Amerício/normas , Guias como Assunto , Coreia (Geográfico) , Plutônio/análise , Plutônio/química , Plutônio/normas , Doses de Radiação , Monitoramento de Radiação/instrumentação , Monitoramento de Radiação/métodos , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
We have developed, as a national standard, a windowless multiwire proportional counting (MWPC) system for gross measurements of alpha- and beta-emitting radionuclides at an uncertainty level below 1%. Various detector characteristics have been studied and several working parameters of the system have been determined in order to achieve an optimized detection capability. The detector is commissioned through an international comparison of the beta emission rate from an extended area (36)Cl source. Correction for the dead time loss is made by the non-extendable dead time method. A linear extrapolation of pulse height spectrum is employed to correct for the loss in the detection efficiency due to discriminating against the events formed from a small number of original ion pairs. The surface emission rate was measured to be 1.84 x 10(3) counts/s with the relative combined standard uncertainty of 0.46%. The measured uncertainty indicates that the constructed MWPC is capable of serving as a national standard.
