Compilation of k0 and related data for NAA in the form of electronic database (IUPAC Technical Report)

Abstract

This report describes the principles underlying a comprehensive electronic database that contains data essential for calculation of analytical results from neutron-activation analysis (NAA) and that is available through IUPAC. The method used is a comparator method called the k0 method, where k0 is a dimensionless factor which is experimentally measured with high accuracy for more than 130 isotopes and which makes use of the gamma spectroscopic line for an analyte isotope relative to a gold comparator. The database contains recommended values for k0 and other relevant nuclear data.

Computer-assisted uncertainty assessment of k0-NAA measurement results

“…The uncertainty propagation factors are based on the exact analytical functions derived from the model k 0 -NAA equation according to the accepted metrological standards [2]. The calculations involved include nuclear data from the internationally recognised database [7] and require knowledge of the experimental data for the specific irradiation and measurement conditions. The results were experimentally validated under the specific k 0 -NAA setup at the TRIGA Mark II reactor of the Jožef Stefan Institute, by comparing the difference between the known amounts of the elements to standard samples and the experimentally determined amounts with the calculated uncertainties for the same samples.…”

“…All the elements of interest could be ticked and added for uncertainty calculation. The parameters k 0 , Q 0 , E r and decay constants l and their uncertainties that are tabulated are taken from the IUPAC database [7] automatically and are displayed for the highlighted element in the topmost window in the middle of the main mask.…”

Comparison of the relative comparator and k0neutron activation analysis techniques for the determination of trace-element concentrations in pyrite

“…The RM is typically a material of known composition which is matrix and compositionally matched to the sample. This technique requires RMs which contain suitable elements at concentrations similar to those in the sample (Kolotov and De Corte, 2004). The limited quantity and high cost of appropriate RMs is a disadvantage of the relative comparator method, as is the difficulty of comparing datasets produced using different RMs.…”

Estudo das covariâncias envolvidas no método k0 de análise por ativação neutrônica

“…A determinação da concentração de um elemento em uma amostra pode ser baseada em diversos métodos de padronização. Um dos métodos de padronização, denominado Tem-se ainda outro método de padronização que é a Análise por Ativação Comparativa [13,14] , que consiste na irradiação simultânea da amostra a ser analisada e uma amostra certificada, com concentração do elemento bem conhecida (padrão) Para contornar essas dificuldades foi desenvolvido o Método k 0 [15][16][17][18] O Método k 0 , em razão de possibilitar a determinação da concentração elementar com grande exatidão, tem sido amplamente aceito por usuários em vários laboratórios do mundo [19][20][21] , incluindo o Brasil [5] . O fator k 0 de um isótopo analisado é função de relações existentes entre as massas atômicas, abundâncias isotópicas, seções de choque para nêutrons térmicos e probabilidades de emissão gama por desintegração para a transição considerada da amostra e do comparador (Au).…”